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      "title": "Columbus's Landfall",
      "caption": "On 12 October 1492, Columbus's three ships anchor off a Bahamian island the Taíno call Guanahani, as a dugout canoe puts out from shore to meet them.",
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      "title": "The Black Death Arrives",
      "caption": "In October 1347, twelve Genoese galleys fleeing Caffa put in at Messina, carrying the Black Death into Europe; within six years the plague kills an estimated 25-50 million people.",
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      "caption": "By 1150, King Suryavarman II's temple-mountain of Angkor Wat nears completion at the heart of the Khmer Empire, its five towers mirrored in a moat more than five kilometres around.",
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      "caption": "Around 740 CE, at the height of Classic Maya civilisation, Tikal's red temple-pyramids rise above the rainforest. Tens of thousands of people depend on the city's rain-fed reservoirs.",
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      "title": "China's First Emperor",
      "caption": "In 210 BCE, as Qin Shi Huang dies, labourers raise the colossal earthen platform of his unfinished Epang Palace outside Xianyang, capital of a China unified eleven years earlier.",
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      "title": "The Bronze Age Collapse",
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      "title": "Monuments Before Farming",
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      "title": "The Oldest Faces Like Ours",
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      "t": 3200000.0,
      "chapterId": "waters-edge",
      "image": "scenes/lucy-afarensis-37a42b5592.webp",
      "thumbnail": "scenes/lucy-afarensis-thumb-86c3894ead.webp",
      "shot": "WATER_EDGE",
      "title": "Lucy's Species",
      "caption": "A small, upright hominin of Lucy's species walks on two legs along a wooded Rift Valley river, still built with long, strong arms for climbing.",
      "events": [
        "australopithecus-afarensis"
      ],
      "location": {
        "label": "Hadar, Ethiopia",
        "presentDay": {
          "lat": 11.16,
          "lon": 40.6
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      "id": "messinian-salt-flats",
      "t": 5600000.0,
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      "thumbnail": "scenes/messinian-salt-flats-thumb-b1c3c511a1.webp",
      "shot": "WATER_EDGE",
      "title": "The Messinian Salinity Crisis",
      "caption": "Cut off from the Atlantic, the Mediterranean shrinks to brine lakes ringed by thick beds of salt; how far the sea actually fell is still debated.",
      "events": [],
      "sound": {
        "stem": "wind",
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        "gain": 0.9
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      "location": {
        "label": "Mediterranean basin",
        "presentDay": {
          "lat": 39.0,
          "lon": 5.0
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    },
    {
      "id": "c4-savanna-hipparion",
      "t": 7000000.0,
      "chapterId": "waters-edge",
      "image": "scenes/c4-savanna-hipparion-bbc3baee71.webp",
      "thumbnail": "scenes/c4-savanna-hipparion-thumb-f16c623955.webp",
      "shot": "WATER_EDGE",
      "title": "East Africa Dries Out",
      "caption": "Coarse new grasses now carpet the plain, and three-toed horses crowd a shrinking waterhole in a drier, more open East Africa.",
      "events": [],
      "sound": {
        "stem": "mammals",
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      "framing": {
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      "pinned": "00c097bfdd0c523f",
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    },
    {
      "id": "miocene-grassland",
      "t": 18000000.0,
      "chapterId": "waters-edge",
      "image": "scenes/miocene-grassland-0ef76c5290.webp",
      "thumbnail": "scenes/miocene-grassland-thumb-fb85b291bf.webp",
      "shot": "WATER_EDGE",
      "title": "The Rise of Grasslands",
      "caption": "Where woodland once stood, grass now dominates the open plains, and three-toed horses graze a horizon no earlier scene has shown.",
      "events": [],
      "sound": {
        "stem": "mammals",
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      "pinned": "93b44eb04685155f",
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    },
    {
      "id": "paraceratherium-woodland",
      "t": 26500000.0,
      "chapterId": "waters-edge",
      "image": "scenes/paraceratherium-woodland-afa324f4bc.webp",
      "thumbnail": "scenes/paraceratherium-woodland-thumb-e36cd23328.webp",
      "shot": "WATER_EDGE",
      "title": "A Giant Hornless Rhino",
      "caption": "About 26.5 million years ago, in what is now northwest China, Paraceratherium, a hornless rhinoceros nearly 5 metres tall at the shoulder and one of the largest land mammals ever, browses the treetops of an open woodland.",
      "events": [
        "paraceratherium"
      ],
      "sound": {
        "stem": "large-animal",
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    {
      "id": "eocene-oligocene-icesheet",
      "t": 33700000.0,
      "chapterId": "waters-edge",
      "image": "scenes/eocene-oligocene-icesheet-4acc5c2520.webp",
      "thumbnail": "scenes/eocene-oligocene-icesheet-thumb-ebb25e408d.webp",
      "shot": "WATER_EDGE",
      "title": "Antarctica's First Ice Sheet",
      "caption": "As Antarctica's first continent-scale ice sheet reaches the sea, Earth leaves the warm world of the early Cenozoic for the icehouse it has lived in ever since.",
      "events": [],
      "sound": {
        "stem": "wind",
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      "pinned": "a2fe73ed75939b32",
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    },
    {
      "id": "eocene-jungle",
      "t": 47500000.0,
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      "image": "scenes/eocene-jungle-23a087f704.webp",
      "thumbnail": "scenes/eocene-jungle-thumb-e669742056.webp",
      "shot": "WATER_EDGE",
      "title": "A Hothouse Rainforest",
      "caption": "About 47.5 million years ago, in a hothouse world still more than 10 °C warmer than today, paratropical rainforest rings the Messel crater lake, in what is now Germany, where tiny early horses come to drink.",
      "events": [
        "messel-pit"
      ],
      "location": {
        "label": "Messel Pit, Germany",
        "presentDay": {
          "lat": 49.918,
          "lon": 8.757
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    },
    {
      "id": "paleocene-recovery",
      "t": 62000000.0,
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      "image": "scenes/paleocene-recovery-b53bff09f0.webp",
      "thumbnail": "scenes/paleocene-recovery-thumb-e087108fc2.webp",
      "shot": "WATER_EDGE",
      "title": "The Age of Mammals Begins",
      "caption": "Four million years after the impact that ended the dinosaurs, mammals have grown into the empty world: a heavy, long-tailed pantodont drinks at a Paleocene forest river.",
      "events": [],
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      "pinned": "735c1240a8062713",
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    },
    {
      "id": "kpg-aftermath",
      "t": 66042900.0,
      "chapterId": "waters-edge",
      "image": "scenes/kpg-aftermath-4e4f24c399.webp",
      "thumbnail": "scenes/kpg-aftermath-thumb-2a9cbfa911.webp",
      "shot": "WATER_EDGE",
      "title": "A Century After Impact",
      "caption": "A century after the impact, ferns carpet the ground where a flowering forest and its dinosaurs stood; the sky has long since cleared, but the world has not recovered.",
      "events": [
        "k-pg-aftermath"
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    {
      "id": "kpg-darkness",
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      "image": "scenes/kpg-darkness-f3b1bc0dc6.webp",
      "thumbnail": "scenes/kpg-darkness-thumb-12a46fec90.webp",
      "shot": "WATER_EDGE",
      "title": "Darkness After Impact",
      "caption": "Days after the impact, a pall of dust and soot blots out the sun over the same estuary; whether the impact's heat set forests alight this far away is still debated.",
      "events": [
        "k-pg-impact"
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    {
      "id": "kpg-arrival",
      "t": 66043000.0,
      "chapterId": "waters-edge",
      "image": "scenes/kpg-arrival-cbcf29fbb9.webp",
      "thumbnail": "scenes/kpg-arrival-thumb-1712910754.webp",
      "shot": "WATER_EDGE",
      "title": "The Asteroid Strikes",
      "caption": "A composite moment: the asteroid that ends the age of dinosaurs, shown in a sky where, thousands of kilometres from its impact, it could never actually have been seen.",
      "events": [
        "k-pg-impact"
      ],
      "sound": {
        "stem": "impact",
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        "gain": 1.0
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      "pinned": "40cf7c5b9d357780",
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    },
    {
      "id": "cretaceous-forest",
      "t": 68000000.0,
      "chapterId": "waters-edge",
      "image": "scenes/cretaceous-forest-1283c72121.webp",
      "thumbnail": "scenes/cretaceous-forest-thumb-c2428b23d4.webp",
      "shot": "WATER_EDGE",
      "title": "Tyrannosaurus and Its Prey",
      "caption": "Two million years before the asteroid, a Tyrannosaurus works the shoreline while Edmontosaurus feed nearby; healed bite marks on their bones show such attacks were often survived.",
      "events": [],
      "sound": {
        "stem": "archosaurs",
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        "gain": 0.9
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      "framing": {
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      "width": 2752,
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    {
      "id": "western-interior-seaway",
      "t": 85000000.0,
      "chapterId": "waters-edge",
      "image": "scenes/western-interior-seaway-27fe54b973.webp",
      "thumbnail": "scenes/western-interior-seaway-thumb-17d1fc8ec6.webp",
      "shot": "WATER_EDGE",
      "title": "The Western Interior Seaway",
      "caption": "About 85 million years ago, a warm, shallow sea splits North America in two. Pteranodon rest on its sandbars while mosasaurs up to 13 metres long hunt offshore.",
      "events": [
        "western-interior-seaway",
        "mosasaurs"
      ],
      "sound": {
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    {
      "id": "mid-cretaceous-pollinators",
      "t": 100000000.0,
      "chapterId": "waters-edge",
      "image": "scenes/mid-cretaceous-pollinators-de7b769800.webp",
      "thumbnail": "scenes/mid-cretaceous-pollinators-thumb-b81e6ee9af.webp",
      "shot": "WATER_EDGE",
      "title": "Flowers and Their Pollinators",
      "caption": "Flowering plants, first known as petal-less water plants some 25 million years earlier, now form a real understory beneath the conifers, visited by small pollen-collecting wasps not yet confidently called bees.",
      "events": [],
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        "stem": "buzzing",
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    {
      "id": "jurassic-floodplain",
      "t": 150000000.0,
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      "image": "scenes/jurassic-floodplain-e9318ea988.webp",
      "thumbnail": "scenes/jurassic-floodplain-thumb-2adb150d49.webp",
      "shot": "WATER_EDGE",
      "title": "The Sauropod Floodplain",
      "caption": "Sauropods wade a Late Jurassic braided river through a floodplain of conifers, cycads and ferns, without a single flower.",
      "events": [],
      "sound": {
        "stem": "sauropod",
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    {
      "id": "jurassic-cycad-pollination",
      "t": 160000000.0,
      "chapterId": "waters-edge",
      "image": "scenes/jurassic-cycad-pollination-9e658639d6.webp",
      "thumbnail": "scenes/jurassic-cycad-pollination-thumb-3cf4c45822.webp",
      "shot": "WATER_EDGE",
      "title": "Pollination Before Flowers",
      "caption": "Long-proboscid scorpionflies feed at the cones of Bennettitales, a probable plant-insect pollination partnership that predates flowers by tens of millions of years.",
      "events": [],
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    {
      "id": "end-triassic-extinction",
      "t": 201500000.0,
      "chapterId": "waters-edge",
      "image": "scenes/end-triassic-extinction-be5f037fab.webp",
      "thumbnail": "scenes/end-triassic-extinction-thumb-7db04f7b9b.webp",
      "shot": "WATER_EDGE",
      "title": "The End-Triassic Extinction",
      "caption": "About 201.5 million years ago, flood basalts pour out as Pangaea begins to split, doubling carbon dioxide. About three quarters of species die out, among them the crocodile-line reptiles that had kept dinosaurs in check.",
      "events": [
        "end-triassic-extinction"
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      "sound": {
        "stem": "volcanic",
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    {
      "id": "late-triassic-dinosaurs",
      "t": 231000000.0,
      "chapterId": "waters-edge",
      "image": "scenes/late-triassic-dinosaurs-2469ef9b6e.webp",
      "thumbnail": "scenes/late-triassic-dinosaurs-thumb-04815181d6.webp",
      "shot": "WATER_EDGE",
      "title": "The First Dinosaurs",
      "caption": "The first dinosaurs are still rare hunters in a world ruled by beaked rhynchosaurs and heavy-headed cynodonts.",
      "events": [],
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    {
      "id": "early-triassic-lystrosaurus",
      "t": 251000000.0,
      "chapterId": "waters-edge",
      "image": "scenes/early-triassic-lystrosaurus-d24cbf0fb1.webp",
      "thumbnail": "scenes/early-triassic-lystrosaurus-thumb-7bad4ecb75.webp",
      "shot": "WATER_EDGE",
      "title": "After the Worst Extinction",
      "caption": "In the super-greenhouse world that followed the worst extinction in Earth's history, one squat, tusked animal makes up nearly the entire land fauna.",
      "events": [],
      "sound": {
        "stem": "large-animal",
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        "gain": 0.85
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      "framing": {
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      "width": 2752,
      "height": 1536
    },
    {
      "id": "permian-conifer-forest",
      "t": 294000000.0,
      "chapterId": "waters-edge",
      "image": "scenes/permian-conifer-forest-0f62e66262.webp",
      "thumbnail": "scenes/permian-conifer-forest-thumb-6de5aa2819.webp",
      "shot": "WATER_EDGE",
      "title": "The Sail-Backed Synapsids",
      "caption": "Where coal-swamp rainforest once stood, open woodland of early conifers now spreads across drier ground, and sail-backed synapsids hunt along its streams.",
      "events": [],
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      "pinned": "56d38ae859aa81c6",
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    },
    {
      "id": "carboniferous-swamp",
      "t": 310000000.0,
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      "image": "scenes/carboniferous-swamp-3cdbf51e9f.webp",
      "thumbnail": "scenes/carboniferous-swamp-thumb-3547e8d6dc.webp",
      "shot": "WATER_EDGE",
      "title": "Giants of the Coal Swamp",
      "caption": "Giant lycopsid trees wall a Carboniferous coal swamp, where oxygen-rich air lets insects and millipedes grow to record sizes.",
      "events": [],
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      "width": 2752,
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    },
    {
      "id": "devonian-estuary",
      "t": 375000000.0,
      "chapterId": "waters-edge",
      "image": "scenes/devonian-estuary-fbf35549aa.webp",
      "thumbnail": "scenes/devonian-estuary-thumb-80adac4329.webp",
      "shot": "WATER_EDGE",
      "title": "The First Forests",
      "caption": "The first forests of Archaeopteris shade a Devonian estuary where lobe-finned fishes haul themselves into the shallows.",
      "events": [],
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        "stem": "water",
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      "pinned": "016ed4555b6092ff",
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    },
    {
      "id": "rhynie-chert",
      "t": 407000000.0,
      "chapterId": "waters-edge",
      "image": "scenes/rhynie-chert-da62e71c0d.webp",
      "thumbnail": "scenes/rhynie-chert-thumb-5b3a2ca8ce.webp",
      "shot": "WATER_EDGE",
      "title": "Life Comes Ashore",
      "caption": "Around hot-spring pools that will one day preserve them in silica, leafless spore-bearing plants shelter the oldest known insect relatives and spiders' arachnid cousins.",
      "events": [],
      "sound": {
        "stem": "geothermal",
        "mode": "loop",
        "gain": 0.8
      },
      "location": {
        "label": "Rhynie, Scotland",
        "presentDay": {
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          "lon": -3.22
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    {
      "id": "ordovician-reef-shore",
      "t": 450000000.0,
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      "image": "scenes/ordovician-reef-shore-911b8a899e.webp",
      "thumbnail": "scenes/ordovician-reef-shore-thumb-bbb4f7b450.webp",
      "shot": "SPLIT_LEVEL",
      "title": "A Bare Coast, a Crowded Sea",
      "caption": "A reef of crinoids, corals and shelled animals teems with life below, hunted by a metre-long nautiloid; above the waterline, the first land plants are known only from their spores.",
      "events": [],
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    },
    {
      "id": "cambrian-seafloor",
      "t": 518000000.0,
      "chapterId": "over-under",
      "image": "scenes/cambrian-seafloor-eb382a9bed.webp",
      "thumbnail": "scenes/cambrian-seafloor-thumb-d18e6b560a.webp",
      "shot": "SPLIT_LEVEL",
      "title": "The Cambrian Explosion",
      "caption": "On the Cambrian sea floor, most major animal groups alive today have appeared within a brief interval — including our own, a jawless swimmer no longer than a fingertip.",
      "events": [],
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    },
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      "id": "cryogenian-snowball",
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      "image": "scenes/cryogenian-snowball-dc5a9d1a7e.webp",
      "thumbnail": "scenes/cryogenian-snowball-thumb-cafe6f6cc7.webp",
      "shot": "SPLIT_LEVEL",
      "title": "Snowball Earth",
      "caption": "During a Snowball Earth glaciation, ice reaches toward the equator, open water may survive only in scattered gaps in the ice, and life hangs on out of sight.",
      "events": [
        "snowball-earth"
      ],
      "sound": {
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      "description": "The reference instant against which every other event's years-before-present value is measured (t = 0). See the README for the fixed 2025 reference-year convention used to compute historical events' t values.\n",
      "citation": "By definition. t = 0 is the timeline's present-day anchor; see sources/events-core/README.md for the reference-year convention.\n"
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      "label": "World population reaches 8 billion",
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      "tags": [
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      "description": "The United Nations estimates that the world's population reaches 8 billion people on 15 November 2022, up from 1 billion around 1804 — a sevenfold increase achieved mostly within two centuries of the roughly 300,000-year history of Homo sapiens.\n",
      "citation": "United Nations Department of Economic and Social Affairs, \"World Population to reach 8 billion on 15 November 2022\" (press release, 2022), via Wikipedia, \"World population\" (accessed 2026-09-18): UN-dated 8 billion milestone, 15 November 2022; 1 billion reached around 1804.\n"
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      "kind": "moment",
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      "tags": [
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      "description": "ChatGPT, a conversational artificial-intelligence chatbot, is released to the public. It reaches an estimated 100 million users within two months and speeds up an ongoing wave of investment in, and public attention to, AI. Its long-term significance is still unfolding.\n",
      "citation": "Wikipedia, \"ChatGPT\" (accessed 2026-09-14). Released 30 November 2022; one million users in five days and 100 million in two months; \"accelerated the AI boom.\" The developer's own announcement page refused a live fetch.\n"
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    {
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      "label": "COVID-19 pandemic",
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      "tags": [
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      "description": "The WHO declares SARS-CoV-2 a public health emergency of international concern on 30 January 2020, then a pandemic on 11 March 2020, as it spreads worldwide; the emergency declaration is lifted on 5 May 2023. More than 7 million confirmed deaths are reported to the WHO over the course of the pandemic, with excess-mortality estimates running several times higher.\n",
      "citation": "Wikipedia, \"COVID-19 pandemic\" (accessed 2026-09-18): PHEIC declared 30 January 2020; characterised a pandemic 11 March 2020; PHEIC ended 5 May 2023; over 7 million confirmed deaths reported to WHO.\n"
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    {
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      "label": "Half of humanity online",
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      "t": 7.0,
      "tags": [
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      "description": "The International Telecommunication Union estimates that by the end of 2018, 51.2% of the world's population (3.9 billion people) is using the Internet. It is the first time more than half of humanity is online. This is a statistical estimate crossing a threshold, not a single observed moment. By 2025 an estimated 6 billion people, about 74%, are online.\n",
      "citation": "International Telecommunication Union (2018). Press release, Geneva, 7 December 2018: \"at the end of 2018, 51.2 per cent of the global population, or 3.9 billion people, will be using the Internet.\" 2025 figure: Wikipedia, \"Global Internet usage\" (accessed 2026-09-14).\n"
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      "tags": [
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      "description": "On 12 December 2015, 196 parties to the UN climate convention adopt the Paris Agreement, committing to hold global warming \"well below 2°C\" above pre-industrial levels and to pursue efforts to limit it to 1.5°C. It enters into force on 4 November 2016.\n",
      "citation": "UNFCCC, \"The Paris Agreement,\" FCCC/CP/2015/10/Add.1, Decision 1/CP.21, adopted at COP21, Paris, 12 December 2015; Article 2.1(a) temperature goal. United Nations, \"The Paris Agreement\" (un.org/en/climatechange/paris-agreement, accessed 2026-09-24): 196 parties; entry into force 4 November 2016.\n"
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      "tags": [
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      "description": "Global installed solar photovoltaic capacity grows more than fivefold in five years, from 41.6 gigawatts in 2010 to 229.1 gigawatts in 2015, while offshore wind turbines begin to spread along temperate coastlines too — the leading edge of a still-early transition away from fossil-fuelled electricity.\n",
      "citation": "Wikipedia, \"Growth of photovoltaics\" (accessed 2026-09-15). Global cumulative installed solar PV capacity 41.6 GW (2010, 76% YoY growth) to 229.1 GW (2015, 27% YoY growth). Review fix (2026-09-15): no global offshore-wind capacity figure for both 2010 and 2015 could be verified live (Wikipedia \"Offshore wind power\" gives only a 2015 European total, 11,027 MW, not a global one for either year), so the offshore-wind clause is kept qualitative rather than quantitative.\n"
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      "tags": [
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      "description": "Apple announces the iPhone in January and releases it in the US in June. It is the first phone with a multi-touch screen, and it does away with almost all physical buttons. Not the first smartphone (see the IBM Simon, 1994), but the design that made the touchscreen smartphone the industry standard.\n",
      "citation": "Wikipedia, \"iPhone (1st generation)\" (accessed 2026-09-14). Announced 9 January 2007 at Macworld, San Francisco; US release 29 June 2007; one millionth unit sold 74 days after release; 6,124,000 units sold before discontinuation on 11 July 2008.\n"
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      "id": "urban-majority-milestone",
      "label": "Half of humanity lives in cities",
      "kind": "moment",
      "tMin": 18.0,
      "tMax": 18.0,
      "t": 18.0,
      "tags": [
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      "description": "For the first time in recorded history, more than half of the world's population lives in cities, in 2007 — up from just 15% in 1900. The share keeps rising, reshaping daily life around the metro systems, office towers and mass transit that a century before did not exist.\n",
      "citation": "Wikipedia, \"Urbanization\" (accessed 2026-09-15), citing United Nations population data: \"just 15% of the world's population lived in cities\" in 1900; \"in 2007, more than 50% of the world population was living in cities, for the first time in human history.\"\n"
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      "tags": [
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      "description": "An international public consortium sequences the roughly 3 billion base pairs of the human genome, from initial NIH funding through a working draft to a finished sequence completed two years ahead of schedule — a foundational resource for modern genomics and medicine.\n",
      "citation": "National Human Genome Research Institute, project timeline. Funding begins 1 October 1990; working draft announced 26 June 2000; completion announced 14 April 2003.\n"
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      "label": "Amazon deforestation accelerates",
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      "tags": [
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      "description": "Brazil's national space agency INPE begins systematic satellite monitoring of Amazon deforestation, recording 21,050 km² of forest cleared in 1988 alone. Clearing peaks at 29,059 km² in 1995 — by far the highest annual total in the record to that point, as new roads cut \"fishbone\" patterns of side-clearings into primary forest, most of it converted to cattle pasture — before a second peak of 27,772 km² in 2004.\n",
      "citation": "Wikipedia, \"Deforestation of the Amazon rainforest\" (accessed 2026-09-18). INPE PRODES annual clearing figures: 21,050 km² (1988), 29,059 km² (1995), 18,161 km² (1996), 27,772 km² (2004); by 1995, 70% of previously forested land in the Amazon (91% of land deforested since 1970) had been converted to cattle ranching.\n"
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      "label": "GPS fully operational",
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      "t": 30.0,
      "tags": [
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      "description": "The US Air Force declares the Global Positioning System fully operational. Its 24-satellite constellation had been complete since December 1993, and a 1983 presidential directive had already promised it for free civilian use. Accurate positioning for everyone follows on 2 May 2000, when the deliberate degrading of the civilian signal (\"Selective Availability\") is switched off.\n",
      "citation": "Wikipedia, \"Global Positioning System\" (accessed 2026-09-14). Initial operational capability December 1993; Full Operational Capability declared by Air Force Space Command April 1995; Selective Availability discontinued 2 May 2000. UNVERIFIED: the often-quoted 17 July 1995 date for Full Operational Capability could not be checked live (the gps.gov page returned 404), so the event is dated to the year only (t = 30 for either date).\n"
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      "label": "First smartphone (IBM Simon)",
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      "tags": [
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      "description": "The IBM Simon Personal Communicator goes on sale. It combines a mobile phone with handheld-organiser (PDA) features and a touchscreen, and is now looked back on as the first true smartphone, though General Magic's Magic Cap devices, released later in 1994, are also counted among the first commercial smartphones. Only about 50,000 Simons were sold in its six months on the market.\n",
      "citation": "Wikipedia, \"IBM Simon\" (accessed 2026-09-14). On sale through BellSouth Cellular from 16 August 1994; prototype shown at COMDEX, 16 November 1992; about 50,000 units sold; \"retrospectively referred to as the first true smartphone.\" Wikipedia, \"Smartphone\" (accessed 2026-09-14): \"The first commercial smartphones are widely recognized to be the IBM Simon Personal Communicator ... and General Magic's Magic Cap devices released by Sony ('magic link') and Motorola ('envoy') in 1994.\"\n"
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    {
      "id": "www-invented",
      "label": "World Wide Web invented",
      "kind": "period",
      "tMin": 34.0,
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      "tags": [
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      "importance": 0.55,
      "description": "Tim Berners-Lee proposes a hypertext system for information management at CERN, then builds the first web browser, server and page, releasing it to the wider Internet in 1991 — the technology underlying the information age's global reach.\n",
      "citation": "Berners-Lee, T. (1989). \"Information Management: A Proposal.\" CERN, 12 March 1989. First web page live 6 August 1991; released publicly 23 August 1991.\n"
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      "label": "Fall of the Berlin Wall",
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      "tMin": 36.0,
      "tMax": 36.0,
      "t": 36.0,
      "tags": [
        "society"
      ],
      "importance": 0.6,
      "description": "Overwhelmed East German border guards at Berlin's checkpoints open the gates to crowds demanding passage, and the Wall that has divided the city since 1961 becomes passable overnight. Within days, Berliners are chipping souvenir fragments from it in daylight; the Wall's fall becomes the defining image of the Cold War's end and is followed within a year by German reunification.\n",
      "citation": "Wikipedia, \"Fall of the Berlin Wall\" (accessed 2026-09-15): checkpoints opened the night of 9 November 1989 after crowds gathered demanding passage; guards overwhelmed, held with little or no identity-checking.\n"
    },
    {
      "id": "chernobyl-disaster",
      "label": "Chernobyl disaster",
      "kind": "moment",
      "tMin": 39.0,
      "tMax": 39.0,
      "t": 39.0,
      "tags": [
        "catastrophe",
        "science-technology"
      ],
      "importance": 0.6,
      "description": "Reactor 4 at the Chernobyl Nuclear Power Plant in the Ukrainian SSR explodes and catches fire, releasing radioactive material across the surrounding region and much of Europe. The nearby city of Pripyat, home to 49,360 people, is evacuated the next day and never resettled; a 30-kilometre exclusion zone is declared ten days later and remains in force.\n",
      "citation": "Wikipedia, \"Chernobyl disaster\" (accessed 2026-09-18): explosion and fire at 01:23 on 26 April 1986, Reactor 4; exclusion zone expanded from 10 km to 30 km within ten days. Wikipedia, \"Pripyat\" (accessed 2026-09-18): population 49,360; evacuated 27 April 1986, one day after the disaster; never resettled.\n"
    },
    {
      "id": "ozone-hole-montreal-protocol",
      "label": "Ozone hole found, then closed by treaty",
      "kind": "period",
      "tMin": 38.0,
      "tMax": 40.0,
      "tags": [
        "earth-climate",
        "science-technology"
      ],
      "importance": 0.55,
      "description": "Farman, Gardiner and Shanklin report a dramatic springtime thinning of the ozone layer over Antarctica — later found to reach 70% — the first clear evidence of a man-made hole in the atmosphere. Within two years 46 nations sign the Montreal Protocol, phasing out the CFCs responsible; ozone levels stabilise by the mid-1990s and later assessments project the Antarctic hole recovering to 1980 levels by around 2066.\n",
      "citation": "Wikipedia, \"Ozone depletion\" (accessed 2026-09-18): Antarctic ozone hole first reported 1985 (Farman et al.), reductions up to 70%; ozone levels stabilised by the mid-1990s; recovery to 1980 levels projected by around 2066 (Antarctica), 2045 (Arctic), 2040 (rest of world). Wikipedia, \"Montreal Protocol\" (accessed 2026-09-18): agreed 16 September 1987 in Montreal, 46 original signatories, entered into force 1 January 1989.\n"
    },
    {
      "id": "internet-tcp-ip-switchover",
      "label": "ARPANET switches to TCP/IP",
      "kind": "moment",
      "tMin": 42.0,
      "tMax": 42.0,
      "t": 42.0,
      "tags": [
        "science-technology",
        "society"
      ],
      "importance": 0.6,
      "description": "On \"flag day\", ARPANET retires its original Network Control Protocol and makes the TCP/IP protocols its standard. TCP/IP is the protocol suite for connecting separate networks together, and the Internet still runs on it today.\n",
      "citation": "Wikipedia, \"ARPANET\" (accessed 2026-09-14). \"On 1 January 1983, known as flag day, TCP/IP protocols became the standard for the ARPANET, replacing the earlier Network Control Protocol.\"\n"
    },
    {
      "id": "shenzhen-sez-designated",
      "label": "Shenzhen designated first Special Economic Zone",
      "kind": "moment",
      "tMin": 45.0,
      "tMax": 45.0,
      "t": 45.0,
      "tags": [
        "society"
      ],
      "importance": 0.5,
      "description": "China designates Shenzhen, then a market town of fishing villages and paddy fields with about 30,000 people, as its first Special Economic Zone, opening it to foreign investment and market reforms. Within forty-five years it grows into a city of some 18.2 million and a global centre of electronics manufacturing.\n",
      "citation": "Wikipedia, \"Shenzhen\" (accessed 2026-09-15). Designated China's first Special Economic Zone in May 1980; population about 30,000 in 1980; population 18.2 million in 2025.\n"
    },
    {
      "id": "smallpox-eradication",
      "label": "Smallpox declared eradicated",
      "kind": "moment",
      "tMin": 45.0,
      "tMax": 45.0,
      "t": 45.0,
      "tags": [
        "science-technology",
        "life"
      ],
      "importance": 0.55,
      "description": "On 8 May 1980 the 33rd World Health Assembly declares smallpox eradicated, the first human disease eliminated worldwide, after a WHO-led vaccination and surveillance campaign; the last naturally occurring case was a hospital worker in Merca, Somalia, in October 1977.\n",
      "citation": "World Health Organization, resolution WHA33.3, \"Declaration of global eradication of smallpox,\" 33rd World Health Assembly, 8 May 1980 (who.int/publications/i/item/ WHA33-3). Last natural case, Merca, Somalia, October 1977: The Lancet, \"A history of eradication — successes, failures, and controversies\" (2012) (author/volume UNVERIFIED).\n"
    },
    {
      "id": "mass-market-personal-computers",
      "label": "Personal computers go mass-market",
      "kind": "moment",
      "tMin": 48.0,
      "tMax": 48.0,
      "t": 48.0,
      "tags": [
        "science-technology",
        "society"
      ],
      "importance": 0.55,
      "description": "The Apple II, Commodore PET 2001 and Tandy TRS-80 all reach the market in 1977 as complete, ready-to-use machines rather than hobbyist kits. They are the first widely successful mass-market personal computers, later called the \"1977 Trinity\" by Byte magazine. IBM's PC of 1981 then sets the \"IBM PC compatible\" standard that most later personal computers follow.\n",
      "citation": "Wikipedia, \"History of personal computers\" (accessed 2026-09-14): the 1977 Trinity, Byte's naming, and dominance by late 1978. Wikipedia, \"IBM Personal Computer\" (accessed 2026-09-14): released 12 August 1981, the basis of the IBM PC compatible de facto standard. The three 1977 release months were not confirmed live, so the event is dated to the year only. Dated to 1977 rather than 1981 because that is when personal computers first became a mass-market product.\n"
    },
    {
      "id": "first-handheld-mobile-call",
      "label": "First public handheld mobile phone call",
      "kind": "moment",
      "tMin": 52.0,
      "tMax": 52.0,
      "t": 52.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.45,
      "description": "Martin Cooper of Motorola, standing on a Manhattan sidewalk, places the first public call from a handheld cellular phone to Joel Engel at rival AT&T. The prototype is a 1.1 kg \"brick\"; a consumer version of the handset goes on sale a decade later, in 1983.\n",
      "citation": "Wikipedia, \"Martin Cooper (inventor)\" (accessed 2026-09-14). Call placed 3 April 1973 on a DynaTAC prototype weighing 2.5 lb (1.1 kg); handset commercially available by 1983 after four iterations.\n"
    },
    {
      "id": "first-microprocessor",
      "label": "Intel 4004, first commercial microprocessor",
      "kind": "moment",
      "tMin": 54.0,
      "tMax": 54.0,
      "t": 54.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.5,
      "description": "Intel releases the 4004, the first microprocessor sold as a stand-alone component: a computer's whole central processor on one chip rather than spread across several. Its designers were Federico Faggin, Marcian Hoff, Stanley Mazor and Masatoshi Shima. The title of \"first microprocessor\" is contested, because earlier single-chip processors existed (Texas Instruments' TMS0100, Four-Phase's AL1 and the then-classified MP944).\n",
      "citation": "Wikipedia, \"Intel 4004\" (accessed 2026-09-14). Released 15 November 1971, announced in Intel's \"Announcing a new era of integrated electronics\" advertisement in that day's Electronic News; \"the first commercially available (sold as a component) microprocessor\". The same page gives the competing claims: TI's TMS0100 (launched 17 September 1971), Four-Phase's AL1 (in a commercial product earlier) and the MP944 (finished 1970, classified until 1998).\n"
    },
    {
      "id": "moon-landing",
      "label": "Moon landing",
      "kind": "moment",
      "tMin": 56.0,
      "tMax": 56.0,
      "t": 56.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.7,
      "description": "Apollo 11 lands the first humans on the Moon. Chosen as a precise, uncontested near-present anchor point for the timeline — the rare event in this set with effectively zero date uncertainty.\n",
      "citation": "NASA (1969). Apollo 11 Mission Report. Neil Armstrong and Buzz Aldrin land at Mare Tranquillitatis on 20 July 1969 UTC.\n"
    },
    {
      "id": "arpanet-first-message",
      "label": "First message over ARPANET",
      "kind": "moment",
      "tMin": 56.0,
      "tMax": 56.0,
      "t": 56.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.5,
      "description": "UCLA student programmer Charley Kline sends the first message over ARPANET to SRI programmer Bill Duvall at the Stanford Research Institute. The receiving computer crashes after two characters, so the first transmission is just \"lo\", from \"login\". ARPANET is the network the Internet grew out of.\n",
      "citation": "Wikipedia, \"ARPANET\" (accessed 2026-09-14), citing the first ARPANET IMP log: 29 October 1969, 10:30 pm PST (06:30 UTC, 30 October 1969), UCLA's SDS Sigma 7 host to SRI's SDS 940 host.\n"
    },
    {
      "id": "containerization",
      "label": "Container shipping remakes world trade",
      "kind": "period",
      "tMin": 45.0,
      "tMax": 69.0,
      "tags": [
        "science-technology",
        "society"
      ],
      "importance": 0.55,
      "description": "Malcom McLean's SS Ideal X sails the first successful container voyage, from Newark to Houston. Standardised steel shipping containers and dedicated gantry-crane terminals spread through the world's ports over the following decades; by 2004 they carry 354 million TEU (twenty-foot container units) of traffic a year, and within a few more years roughly nine-tenths of the world's non-bulk seaborne trade moves in a box.\n",
      "citation": "Wikipedia, \"Containerization\" (accessed 2026-09-15). SS Ideal X voyage 26 April 1956; ISO container standardisation 1968-1970; global container traffic 354 million TEU in 2004, ~82% handled by the top 100 ports; roughly 90% of non-bulk cargo moved by containers by 2009.\n"
    },
    {
      "id": "green-revolution",
      "label": "Green Revolution",
      "kind": "period",
      "tMin": 55.0,
      "tMax": 65.0,
      "tags": [
        "science-technology",
        "society"
      ],
      "importance": 0.65,
      "description": "Norman Borlaug's short-stemmed, disease-resistant Mexican wheat lines, and the high-yield rice varieties (such as IR8, released 1966) bred alongside them, spread through South Asia and are credited with saving perhaps a billion people from famine. India's wheat harvest rises from about 10 million tonnes a year in the 1960s to 73 million by 2006.\n",
      "citation": "Wikipedia, \"Green Revolution\" (accessed 2026-09-15). Borlaug hired 1940 to lead Mexico's agricultural research; Nobel Peace Prize 1970; India wheat production 10 Mt (1960s) to 73 Mt (2006); IR8 rice released 1966, yielding up to ~10 t/ha under optimal conditions by 1968. Review fix (2026-09-15): dropped this page's separate claim of India rice yields rising ~2 to ~6 t/ha (1960s to mid-1990s) -- Wikipedia \"Rice production in India\"'s own yield table gives India's actual national average as ~1.0 t/ha (1960s) to ~1.9 t/ha (1996-97/1997-98), roughly a third of that figure, so it is not used as a national-average claim.\n"
    },
    {
      "id": "gagarin-first-spaceflight",
      "label": "First human spaceflight",
      "kind": "moment",
      "tMin": 64.0,
      "tMax": 64.0,
      "t": 64.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.45,
      "description": "Yuri Gagarin completes a single orbit of Earth aboard Vostok 1, becoming the first human in space, and returns safely to Earth the same day.\n",
      "citation": "Launch record, Vostok 1, 12 April 1961, 06:07 UTC, Baikonur Cosmodrome; single orbit, landing 07:55 UTC the same day. Uncontested.\n"
    },
    {
      "id": "keeling-curve-begins",
      "label": "Keeling begins measuring atmospheric CO2",
      "kind": "moment",
      "tMin": 67.0,
      "tMax": 67.0,
      "t": 67.0,
      "tags": [
        "science-technology",
        "earth-climate"
      ],
      "importance": 0.45,
      "description": "Charles David Keeling, at the Scripps Institution of Oceanography, begins continuous measurement of atmospheric CO2 at Mauna Loa Observatory, recording 313 parts per million. The resulting Keeling Curve becomes the foundational record of humanity's own atmospheric measurement of itself, still running today.\n",
      "citation": "Wikipedia, \"Keeling Curve\" (accessed 2026-09-18): measurements begin March 1958, Mauna Loa Observatory, Scripps Institution of Oceanography; initial reading 313 ppm; prior Kew Observatory measurements (1898-1901) averaged 274 ppm.\n"
    },
    {
      "id": "integrated-circuit-invented",
      "label": "Integrated circuit invented",
      "kind": "moment",
      "tMin": 67.0,
      "tMax": 67.0,
      "t": 67.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.55,
      "description": "Jack Kilby demonstrates the first working integrated circuit, putting several electronic components on a single piece of semiconductor; about six months later Robert Noyce at Fairchild Semiconductor develops the first practical monolithic chip. Every later computer, phone and network builds on the microchip.\n",
      "citation": "Wikipedia, \"Integrated circuit\" (accessed 2026-09-14). Kilby's first working example demonstrated 12 September 1958; Noyce's monolithic IC about six months later (1959). Kilby shared the 2000 Nobel Prize in Physics for the invention (the nobelprize.org facts page refused a live fetch; confirmed via Wikipedia only).\n"
    },
    {
      "id": "sputnik-1-launch",
      "label": "First artificial satellite",
      "kind": "moment",
      "tMin": 68.0,
      "tMax": 68.0,
      "t": 68.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.45,
      "description": "The Soviet Union launches Sputnik 1 from Baikonur, the first artificial satellite to orbit Earth, opening the Space Age.\n",
      "citation": "Launch record, Sputnik 1, 4 October 1957, 19:28:34 UTC, Site No. 1, Baikonur Cosmodrome; initial orbit 223 x 950 km. Uncontested.\n"
    },
    {
      "id": "dna-double-helix",
      "label": "DNA double helix described",
      "kind": "moment",
      "tMin": 72.0,
      "tMax": 72.0,
      "t": 72.0,
      "tags": [
        "science-technology",
        "life"
      ],
      "importance": 0.6,
      "description": "James Watson and Francis Crick publish the double-helix structure of DNA in Nature, built on Rosalind Franklin's and Maurice Wilkins's X-ray diffraction data — the structural discovery underlying all of modern molecular biology and genetics.\n",
      "citation": "Watson, J.D. & Crick, F.H.C. (1953). \"Molecular structure of nucleic acids: a structure for deoxyribose nucleic acid.\" Nature, 171(4356), 737-738. Published 25 April 1953.\n"
    },
    {
      "id": "postwar-suburban-boom",
      "label": "Postwar highway and suburban boom",
      "kind": "period",
      "tMin": 65.0,
      "tMax": 80.0,
      "tags": [
        "society",
        "science-technology"
      ],
      "importance": 0.55,
      "description": "In the fifteen years after the Second World War, the United States builds a new mass-produced suburbia and the highways to connect it. Levittown, New York, the first mass-produced suburb, raises 17,447 houses in under four years; the Federal-Aid Highway Act of 1956 then authorises 40,000 miles of new divided interstate highway, the largest public-works programme in the country's history. Car and home ownership become mass-market goods within a single generation.\n",
      "citation": "Wikipedia, \"Levittown, New York\" and \"Interstate Highway System\" (both accessed 2026-09-15). Levittown built 1947-1951, 17,447 houses, peak rate 30 houses/day. Federal-Aid Highway Act of 1956 signed June 1956, authorising 40,000 miles of divided highway.\n"
    },
    {
      "id": "indian-independence",
      "label": "Independence of India and Pakistan",
      "kind": "moment",
      "tMin": 78.0,
      "tMax": 78.0,
      "t": 78.0,
      "tags": [
        "society"
      ],
      "importance": 0.55,
      "description": "British rule in India ends on 15 August 1947 with the partition of the Raj into the independent dominions of India and Pakistan. Partition displaces an estimated 10-20 million people. It opens two decades in which most of Britain's colonies in Asia and Africa become independent.\n",
      "citation": "Via Wikipedia \"Partition of India\" and \"Decolonisation of Africa\" (searched 2026-09-24): Indian Independence Act 1947, independence 14-15 August 1947; 10-20 million displaced.\n"
    },
    {
      "id": "transistor-invented",
      "label": "Transistor invented",
      "kind": "moment",
      "tMin": 77.0,
      "tMax": 78.0,
      "t": 78.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.6,
      "description": "John Bardeen and Walter Brattain at Bell Labs get a point-contact germanium device to amplify a signal, between 17 November and 23 December 1947 — the first working transistor, which comes to replace the vacuum tube and underlies nearly all modern solid-state electronics and computing. Bell Labs made no public announcement before June 1948, but this session could not confirm an exact announcement date.\n",
      "citation": "Bardeen, J. & Brattain, W.H. (1948). \"The transistor, a semi-conductor triode.\" Physical Review, 74(2), 230-231. Point-contact device demonstrated 17 November-23 December 1947 at Bell Labs, Murray Hill, New Jersey. UNVERIFIED: the commonly cited 30 June 1948 public-announcement date could not be confirmed live against Wikipedia \"Transistor\" or \"History of the transistor\" — both state only \"not before June 1948,\" with no specific day. Dropped from the description per instruction rather than asserted; flag for a direct check against Bell Labs' own press-conference record or the Physical Review submission/publication dates before relying on the day-level figure.\n"
    },
    {
      "id": "trinity-test",
      "label": "First nuclear weapon detonated",
      "kind": "moment",
      "tMin": 80.0,
      "tMax": 80.0,
      "t": 80.0,
      "tags": [
        "science-technology",
        "society"
      ],
      "importance": 0.6,
      "description": "The US Army detonates the first nuclear weapon, a plutonium implosion device, at the Trinity site in the New Mexico desert, three weeks before the atomic bombings of Hiroshima and Nagasaki — opening the nuclear age.\n",
      "citation": "US Department of Energy / Manhattan Project records. Trinity test, 16 July 1945, 05:29:21 Mountain War Time, Jornada del Muerto desert, New Mexico; yield ~24.8 kt. Uncontested — among the most precisely documented events of the 20th century.\n"
    },
    {
      "id": "d-day-normandy-landings",
      "label": "D-Day, the Normandy landings",
      "kind": "moment",
      "tMin": 81.0,
      "tMax": 81.0,
      "t": 81.0,
      "tags": [
        "catastrophe",
        "society"
      ],
      "importance": 0.6,
      "description": "Allied forces land on five beaches along the Normandy coast in the largest seaborne invasion in history, opening the Western Front against Nazi Germany. About 132,000 troops come ashore by landing craft on the first day, alongside a further 24,000 airborne troops dropped by parachute and glider overnight — some 156,000 in total; the campaign that follows leads to the liberation of Western Europe within a year.\n",
      "citation": "Wikipedia, \"Normandy landings\" (accessed 2026-09-15): 6 June 1944; Utah, Omaha, Gold, Juno and Sword beaches; approximately 156,000 troops landed on D-Day in total, including 24,000 airborne troops.\n"
    },
    {
      "id": "world-war-ii",
      "label": "The Second World War",
      "kind": "period",
      "tMin": 79.33,
      "tMax": 85.33,
      "tags": [
        "catastrophe",
        "society"
      ],
      "importance": 0.7,
      "description": "Beginning with Germany's invasion of Poland, the Second World War becomes the deadliest conflict in human history, fought across Europe, the Pacific, North Africa and beyond and marked by genocide, including the Holocaust, and the first use of nuclear weapons. It ends with Japan's surrender on 2 September 1945. Estimates of the total dead, the majority civilians, range from 60 to 75 million.\n",
      "citation": "Wikipedia, \"World War II\" (accessed 2026-09-15): began 1 September 1939; ended 2 September 1945; estimated 60-75 million deaths, military and civilian, a majority of them civilian.\n"
    },
    {
      "id": "ginza-modern-urban-culture",
      "label": "Ginza's mass urban culture",
      "kind": "period",
      "tMin": 91.0,
      "tMax": 101.0,
      "tags": [
        "society",
        "science-technology"
      ],
      "importance": 0.5,
      "description": "Tokyo's Ginza district becomes interwar Japan's showcase of a new, first-of-its- kind mass urban lifestyle: a Ginza department store lets customers keep their shoes on indoors from 1924, Japan's first radio broadcasts begin the following year, and Tokyo's first subway line — Asia's oldest, opened in 1927 — reaches Ginza itself only in 1934, as crowds throng the district for \"Ginbura,\" the fashionable pastime of strolling Ginza simply to see and be seen.\n",
      "citation": "Wikipedia, \"Department store\" (accessed 2026-09-15): \"In 1924, Matsuzakaya store in Ginza allowed street shoes to be worn indoors.\" Wikipedia, \"NHK\" (accessed 2026-09-15): Tokyo Broadcasting Station begins radio broadcasts in 1925. Wikipedia, \"Ginza Line\" (accessed 2026-09-15): Ueno-Asakusa section opens 30 December 1927, Asia's oldest subway line; reaches Shimbashi 21 June 1934. Wikipedia, \"Ginza\" (accessed 2026-09-15): the \"Ginbura\" strolling custom \"developing strongly between the two world wars.\"\n"
    },
    {
      "id": "penicillin-discovery",
      "label": "Penicillin discovered",
      "kind": "moment",
      "tMin": 96.0,
      "tMax": 97.0,
      "t": 97.0,
      "tags": [
        "science-technology",
        "life"
      ],
      "importance": 0.6,
      "description": "Alexander Fleming notices that a mould contaminating a bacterial culture plate at St Mary's Hospital, London, has killed the surrounding bacteria — the observation that opens the antibiotic era, though mass production waits until the 1940s.\n",
      "citation": "Fleming, A. (1929). \"On the antibacterial action of cultures of a penicillium, with special reference to their use in the isolation of B. influenzae.\" British Journal of Experimental Pathology, 10(3), 226-236 (received 10 May 1929, describing the culture-plate observation dated 3 September 1928).\n"
    },
    {
      "id": "end-of-the-ottoman-empire",
      "label": "End of the Ottoman Empire",
      "kind": "moment",
      "tMin": 103.0,
      "tMax": 103.0,
      "t": 103.0,
      "tags": [
        "society"
      ],
      "importance": 0.5,
      "description": "Defeated in the First World War and partitioned by the Allies, the Ottoman Empire ends when the Grand National Assembly in Ankara abolishes the sultanate on 1 November 1922. The Republic of Turkey is proclaimed the following year.\n",
      "citation": "Via Wikipedia \"Abolition of the Ottoman sultanate\" and \"Republic of Turkey\" (searched 2026-09-24): sultanate abolished 1 November 1922; republic proclaimed 29 October 1923.\n"
    },
    {
      "id": "influenza-1918-pandemic",
      "label": "1918 influenza pandemic",
      "kind": "period",
      "tMin": 105.0,
      "tMax": 107.0,
      "tags": [
        "catastrophe",
        "society"
      ],
      "importance": 0.6,
      "description": "An influenza pandemic spreads worldwide from February 1918 to April 1920, infecting an estimated third of the global population, some 500 million people. Death-toll estimates vary widely and are genuinely contested, from 17 million to 100 million, with 25-50 million most commonly cited — making it, by the low end of that range alone, deadlier than the First World War it overlaps.\n",
      "citation": "Wikipedia, \"1918 influenza pandemic\" (accessed 2026-09-18): February 1918 - April 1920; ~500 million infected (nearly a third of world population); deaths \"generally accepted\" at 25-50 million, with cited estimates ranging 17-100 million.\n"
    },
    {
      "id": "russian-revolution",
      "label": "Russian Revolution",
      "kind": "moment",
      "tMin": 108.0,
      "tMax": 108.0,
      "t": 108.0,
      "tags": [
        "society"
      ],
      "importance": 0.55,
      "description": "Amid the losses of the First World War, the February Revolution of 1917 forces Tsar Nicholas II to abdicate, ending the Russian Empire and three centuries of Romanov rule. The Bolsheviks seize power in the October Revolution later that year.\n",
      "citation": "Via Wikipedia \"Russian Revolution\" and \"Nicholas II\" (searched 2026-09-24): abdication of Nicholas II, 15 March 1917 (2 March Old Style); October Revolution, 7 November 1917 (25 October Old Style).\n"
    },
    {
      "id": "world-war-i",
      "label": "The First World War",
      "kind": "period",
      "tMin": 106.14,
      "tMax": 110.43,
      "tags": [
        "catastrophe",
        "society"
      ],
      "importance": 0.65,
      "description": "Beginning with Austria-Hungary's declaration of war on Serbia after the assassination of Archduke Franz Ferdinand, the First World War draws in every major power and spreads across Europe, the Middle East, Africa and beyond, fought largely from fixed trench lines on its Western Front — the Somme among them. It ends with the Armistice of 11 November 1918. Estimates of the total dead, military and civilian, range from 15 to 22 million.\n",
      "citation": "Wikipedia, \"World War I\" (accessed 2026-09-15): began 28 July 1914; ended with the Armistice of 11 November 1918; estimated 15-22 million deaths, military and civilian.\n"
    },
    {
      "id": "battle-of-the-somme",
      "label": "Battle of the Somme",
      "kind": "period",
      "tMin": 108.12,
      "tMax": 108.5,
      "tags": [
        "catastrophe",
        "society"
      ],
      "importance": 0.55,
      "description": "Allied and German forces fight a four-and-a-half-month battle along the Somme river in northern France, one of the largest and costliest battles of the First World War. More than three million men take part; over a million are killed, wounded or reported missing on both sides, for a front line that moves only a few kilometres.\n",
      "citation": "Wikipedia, \"Battle of the Somme\" (accessed 2026-09-15): 1 July - 18 November 1916; over 3 million combatants; British casualties ~420,000, French ~200,000, German 237,159-429,209.\n"
    },
    {
      "id": "general-relativity",
      "label": "General relativity published",
      "kind": "moment",
      "tMin": 109.0,
      "tMax": 110.0,
      "t": 110.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.55,
      "description": "Albert Einstein presents the field equations of general relativity to the Prussian Academy of Sciences, replacing Newtonian gravity with curved spacetime; the full theory appears in print the following year.\n",
      "citation": "Einstein, A. (1915). Sitzungsberichte der Preussischen Akademie der Wissenschaften, presented 25 November 1915. Full theory: Einstein, A. (1916). \"Die Grundlage der allgemeinen Relativitatstheorie.\" Annalen der Physik, 354(7), 769-822.\n"
    },
    {
      "id": "ford-model-t-assembly-line",
      "label": "Ford's moving assembly line",
      "kind": "moment",
      "tMin": 112.0,
      "tMax": 112.0,
      "t": 112.0,
      "tags": [
        "science-technology",
        "society"
      ],
      "importance": 0.5,
      "description": "Henry Ford's Highland Park plant in Michigan introduces the moving assembly line for the Model T, cutting chassis assembly time from over twelve hours to 93 minutes by the following year. Combined with the internal combustion engine it puts on the road, the technique makes the automobile a mass-market product and becomes the template for 20th-century manufacturing.\n",
      "citation": "Wikipedia, \"Ford Model T\" (accessed 2026-09-15). Moving assembly line introduced 7 October 1913 at the Highland Park plant; assembly time cut from 12+ hours to 93 minutes by 1914.\n"
    },
    {
      "id": "fall-of-the-qing",
      "label": "Fall of the Qing dynasty",
      "kind": "moment",
      "tMin": 113.0,
      "tMax": 113.0,
      "t": 113.0,
      "tags": [
        "society"
      ],
      "importance": 0.5,
      "description": "The Xinhai Revolution, which began with the Wuchang Uprising in October 1911, ends more than two thousand years of imperial rule in China. The six-year-old Xuantong Emperor, Puyi, abdicates on 12 February 1912, and the Republic of China takes the Qing's place.\n",
      "citation": "Via Wikipedia \"1911 Revolution\" and \"Puyi\" (searched 2026-09-24): Wuchang Uprising, 10 October 1911; abdication edict of the Xuantong Emperor, 12 February 1912.\n"
    },
    {
      "id": "haber-bosch-process",
      "label": "Haber-Bosch fertiliser process",
      "kind": "period",
      "tMin": 112.0,
      "tMax": 116.0,
      "tags": [
        "science-technology",
        "earth-climate"
      ],
      "importance": 0.65,
      "description": "Fritz Haber's bench-scale synthesis of ammonia from atmospheric nitrogen is scaled by Carl Bosch into industrial production at BASF's Oppau plant — the process that now fixes roughly half the nitrogen in living human bodies via synthetic fertiliser, and a major driver of 20th-century population growth and cropland expansion.\n",
      "citation": "Smil, V. (2001). Enriching the Earth: Fritz Haber, Carl Bosch, and the Transformation of World Food Production. MIT Press. Lab demonstration summer 1909; Oppau industrial-scale production begins 1913, reaching 20 t/day by 1914. The oft- cited \"feeds nearly half of humanity\" figure traces to Smil and was not independently re-derived here.\n"
    },
    {
      "id": "wright-flyer-first-flight",
      "label": "First powered flight",
      "kind": "moment",
      "tMin": 122.0,
      "tMax": 122.0,
      "t": 122.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.65,
      "description": "Orville Wright pilots the Wright Flyer roughly 120 feet over the dunes at Kitty Hawk, North Carolina — the first sustained, controlled, powered flight of a heavier-than-air aircraft, opening the age of aviation less than six decades before the first orbital and human spaceflights below.\n",
      "citation": "Wright, O. (1903). Telegram to Bishop Milton Wright, 17 December 1903. Library of Congress / World Digital Library. Uncontested.\n"
    },
    {
      "id": "krakatoa-eruption",
      "label": "Krakatoa eruption",
      "kind": "moment",
      "tMin": 142.0,
      "tMax": 142.0,
      "t": 142.0,
      "tags": [
        "catastrophe",
        "earth-climate"
      ],
      "importance": 0.45,
      "description": "After three months of smaller eruptions, Krakatau in the Sunda Strait between Java and Sumatra erupts climactically on 26-27 August 1883 (VEI 6), collapsing most of the island into a caldera. Its explosions were heard some 4,800 km away, and the tsunamis it raised killed more than 36,000 people on the surrounding coasts.\n",
      "citation": "Simkin, T. & Fiske, R.S. (1983). Krakatau 1883: The Volcanic Eruption and Its Effects. Washington, D.C.: Smithsonian Institution Press. Activity from 20 May 1883, climax 26-27 August, VEI 6, >36,000 dead, heard at Rodrigues ~4,800 km away: NOAA NCEI, \"On This Day: Historic Krakatau Eruption of 1883\"; Wikipedia, \"1883 eruption of Krakatoa\" (accessed 2026-09-24). The widely quoted exact toll of 36,417 was not confirmed against Simkin & Fiske.\n"
    },
    {
      "id": "edison-electric-light",
      "label": "Edison's practical incandescent bulb",
      "kind": "moment",
      "tMin": 146.0,
      "tMax": 146.0,
      "t": 146.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.5,
      "description": "Thomas Edison's laboratory arrives at a commercially viable carbon-filament incandescent bulb, filing a patent weeks later and publicly demonstrating it at Menlo Park that December — not the first electric light ever made, but the first practical, long-lasting, mass-producible one.\n",
      "citation": "Wikipedia, \"Thomas Edison\" (accessed 2026-09-14). Viable design 21 October 1879; patent filed 4 November 1879; public demonstration December 1879.\n"
    },
    {
      "id": "mass-european-emigration",
      "label": "Mass European emigration to the Americas",
      "kind": "period",
      "tMin": 92.0,
      "tMax": 210.0,
      "tags": [
        "society"
      ],
      "importance": 0.45,
      "description": "From the end of the Napoleonic Wars to the Great Depression, roughly 65 million people leave Europe, the majority of them for the Americas, one of the largest voluntary mass migrations in recorded history; the United States alone receives some 32 million arrivals between 1821 and 1932, with Argentina, Canada and Brazil each receiving several million more. Economic historians date the era's high-volume phase -- driven by famine, land pressure, industrialisation and cheap steamship passage -- from around 1850, with Italians and other southern and eastern Europeans joining the earlier-dominant British, Irish and German flows.\n",
      "citation": "Wikipedia, \"European emigration\" (accessed 2026-09-17): 65 million people leave Europe 1815-1933, primarily to the Americas; United States receives 32,244,000 arrivals 1821-1932, Argentina 6,405,000 (1856-1932), Canada 5,206,000 (1831-1932), Brazil 4,431,000 (1818-1932). Hatton, T.J. & Williamson, J.G. (1998). The Age of Mass Migration: Causes and Economic Impact. Oxford University Press (dates the era's high-volume phase from c. 1850; not independently read this session). O Grada, C. (1999). Black '47 and Beyond: The Great Irish Famine in History, Economy, and Memory. Princeton University Press (Irish Famine-era emigration through Cobh/Queenstown peaking c. 1850).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "migration",
        "origin": {
          "lat": 51.85,
          "lon": -8.29
        },
        "destination": {
          "lat": 40.7,
          "lon": -74.0
        },
        "established": 175.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 210.0
          }
        ]
      }
    },
    {
      "id": "pasteur-koch-germ-theory",
      "label": "Germ theory of disease established",
      "kind": "period",
      "tMin": 142.0,
      "tMax": 166.0,
      "tags": [
        "science-technology",
        "life"
      ],
      "importance": 0.75,
      "description": "Louis Pasteur's 1859 swan-neck flask experiments show that a sterilised broth does not spontaneously generate life, undermining spontaneous generation; Robert Koch then identifies the specific bacteria causing anthrax (1876) and tuberculosis (1882), and his assistant Friedrich Loeffler formalises Koch's postulates in 1883 — together establishing that specific microorganisms cause specific infectious diseases, a foundation of modern medicine and public health.\n",
      "citation": "Wikipedia, \"Louis Pasteur\" and \"Robert Koch\" (accessed 2026-09-14). Swan-neck flask experiment dated 1859 per Wikipedia, \"Spontaneous generation\" (accessed 2026-09-14) — corrects an earlier draft's 1861. Koch's anthrax (1876) and tuberculosis (1882) identifications, and the 1883 postulates credited to Loeffler, confirmed live; the bounding interval is a curatorial choice among several credible milestones in a continuous scientific development, not a single literature-defined span.\n"
    },
    {
      "id": "first-transcontinental-railroad",
      "label": "First transcontinental railroad completed",
      "kind": "moment",
      "tMin": 156.0,
      "tMax": 156.0,
      "t": 156.0,
      "tags": [
        "science-technology",
        "society"
      ],
      "importance": 0.55,
      "description": "On 10 May 1869 a ceremonial golden spike at Promontory Summit, Utah Territory, joins the Central Pacific line built east from Sacramento to the Union Pacific line built west from Omaha, and a telegraph signal carries the word \"DONE\" across the country. Most of the Central Pacific's labour was done by Chinese workers: some 90 per cent of its workforce by 1867, 10,000-15,000 men at the peak. Hundreds, and possibly more than a thousand, died during its construction.\n",
      "citation": "Chinese Railroad Workers in North America Project, Stanford University, via Stanford Report, \"Giving voice to Chinese railroad workers\" (April 2019, accessed 2026-09-24): ~90% of the Central Pacific workforce Chinese by February 1867; 10,000-15,000 at peak, perhaps 20,000 in total; \"hundreds, possibly more than a thousand\" deaths. Utley, R.M. & Ketterson, F.A. Jr. (1969). Golden Spike. National Park Service Historical Handbook Series No. 40. Date and 12:47 p.m. \"DONE\" telegram: Utah History to Go, \"Golden Spike National Historic Site\" (historytogo.utah.gov/golden-spike, accessed 2026-09-24); Library of Congress, \"Today in History - May 10\".\n"
    },
    {
      "id": "darwin-natural-selection",
      "label": "Evolution by natural selection published",
      "kind": "moment",
      "tMin": 166.0,
      "tMax": 167.0,
      "t": 166.0,
      "tags": [
        "science-technology",
        "life"
      ],
      "importance": 0.8,
      "description": "Charles Darwin and Alfred Russel Wallace's joint paper on natural selection is read to the Linnean Society in July 1858; Darwin's On the Origin of Species follows in November 1859, proposing natural selection as evolution's mechanism — the publication that establishes the theory underlying all subsequent biology, though the biological events it describes (`hominins` onward, and the deep-time entries elsewhere in this file) are each dated independently of this publication.\n",
      "citation": "Wikipedia, \"On the Origin of Species\" (accessed 2026-09-14). Linnean Society reading 1 July 1858; Origin of Species published 24 November 1859.\n"
    },
    {
      "id": "tambora-eruption",
      "label": "Tambora eruption",
      "kind": "moment",
      "tMin": 210.0,
      "tMax": 210.0,
      "t": 210.0,
      "tags": [
        "catastrophe",
        "earth-climate"
      ],
      "importance": 0.55,
      "description": "Mount Tambora on Sumbawa, in present-day Indonesia, erupts climactically on 10 April 1815 (VEI 7), the largest eruption in recorded history; more than 71,000 people die on Sumbawa and Lombok during or after it. Some 60 megatonnes of sulphur injected into the stratosphere cool the Northern Hemisphere, bringing crop failures and famine in 1816, the \"Year Without a Summer.\"\n",
      "citation": "Oppenheimer, C. (2003). \"Climatic, environmental and human consequences of the largest known historic eruption: Tambora volcano (Indonesia) 1815.\" Progress in Physical Geography, 27(2), 230-259, doi:10.1191/0309133303pp379ra — ~50 km3 dense-rock equivalent, >71,000 dead on Sumbawa and Lombok, ~60 Mt sulphur, causal link to 1816. Climactic eruption 10 April 1815, VEI 7: Encyclopaedia Britannica, \"How the 1815 eruption of Mount Tambora produced the 'Year Without a Summer'\" (accessed 2026-09-24). Issue number (2) UNVERIFIED.\n"
    },
    {
      "id": "holy-roman-empire-dissolved",
      "label": "Holy Roman Empire dissolved",
      "kind": "moment",
      "tMin": 219.0,
      "tMax": 219.0,
      "t": 219.0,
      "tags": [
        "society"
      ],
      "importance": 0.35,
      "description": "After Napoleon's victory at Austerlitz and the secession of the German states of his Confederation of the Rhine, Francis II abdicates on 6 August 1806 and declares the Holy Roman Empire dissolved, 844 years after Otto I's coronation. He continues to rule as Francis I, Emperor of Austria.\n",
      "citation": "Via Wikipedia \"Dissolution of the Holy Roman Empire\" (searched 2026-09-24): Confederation of the Rhine members secede 1 August 1806; Francis II abdicates and dissolves the empire, 6 August 1806.\n"
    },
    {
      "id": "industrial-revolution",
      "label": "Industrial Revolution",
      "kind": "period",
      "tMin": 185.0,
      "tMax": 265.0,
      "tags": [
        "science-technology",
        "society"
      ],
      "importance": 0.6,
      "description": "Mechanised manufacturing, steam power and the factory system transform Britain's economy and, within a century, the rest of the industrialised world. Historians disagree on precise bounds — Ashton's 1760-1830 and the wider 1760-1840 convention are both in common use — so the interval reflects that disagreement.\n",
      "citation": "Ashton, T.S. (1948). The Industrial Revolution 1760-1830. Oxford University Press. Conventional bracket widened to 1760-1840 by later historians (e.g. Encyclopaedia Britannica, \"Industrial Revolution\").\n"
    },
    {
      "id": "canton-system",
      "label": "Canton System",
      "kind": "period",
      "tMin": 183.0,
      "tMax": 268.0,
      "tags": [
        "society"
      ],
      "importance": 0.4,
      "description": "Qing China confines all Western maritime trade to Canton (Guangzhou), where foreign merchants live and trade from the Thirteen Factories on the Pearl River and deal only through a licensed guild of Chinese Hong merchants, the Cohong. The system ends with the 1842 Treaty of Nanking after the First Opium War, which abolished the Cohong monopoly and opened treaty ports.\n",
      "citation": "Van Dyke, P.A. (2005). The Canton Trade: Life and Enterprise on the China Coast, 1700-1845. Hong Kong University Press. Dates (1757 edict of the Qianlong Emperor; Cohong sanctioned 1760; ended by Article V of the 1842 Treaty of Nanking): Wikipedia, \"Canton System\" and \"Thirteen Factories\" (accessed 2026-09-24); Encyclopaedia Britannica, \"Canton system.\"\n"
    },
    {
      "id": "haitian-revolution",
      "label": "Haitian Revolution",
      "kind": "period",
      "tMin": 221.0,
      "tMax": 234.0,
      "tags": [
        "society"
      ],
      "importance": 0.5,
      "description": "Enslaved people in the French colony of Saint-Domingue, the most profitable colony of the eighteenth-century Atlantic world, rise in August 1791, force emancipation by 1794 and, under Toussaint Louverture and then Jean-Jacques Dessalines, defeat Napoleon's expedition. Independence is declared on 1 January 1804, making Haiti the first state founded through a successful slave revolt.\n",
      "citation": "Dubois, L. (2004). Avengers of the New World: The Story of the Haitian Revolution. Cambridge, MA: Belknap Press of Harvard University Press — uprising 1791, emancipation ratified by Paris 1794, \"the first and only successful slave revolution in the Americas.\" Bois Caïman ceremony August 1791 and independence 1 January 1804: Wikipedia, \"Haitian Revolution\" (accessed 2026-09-24).\n"
    },
    {
      "id": "jenner-smallpox-vaccine",
      "label": "Jenner's smallpox vaccine",
      "kind": "moment",
      "tMin": 229.0,
      "tMax": 229.0,
      "t": 229.0,
      "tags": [
        "science-technology",
        "life"
      ],
      "importance": 0.6,
      "description": "On 14 May 1796 the English physician Edward Jenner inoculates eight-year-old James Phipps with material from a milkmaid's cowpox lesion, then shows the boy is immune to smallpox. Jenner publishes the method in 1798, founding vaccination.\n",
      "citation": "Riedel, S. (2005). \"Edward Jenner and the history of smallpox and vaccination.\" Baylor University Medical Center Proceedings, 18(1), 21-25, doi:10.1080/08998280.2005.11928028. Date 14 May 1796, James Phipps, cowpox from Sarah Nelmes, and 1798 \"An Inquiry into the Causes and Effects of the Variolae Vaccinae\": Science Museum Group Collection, \"James Phipps\" (accessed 2026-09-24).\n"
    },
    {
      "id": "edo-million-city",
      "label": "Edo, a city of a million",
      "kind": "period",
      "tMin": 157.0,
      "tMax": 304.0,
      "tags": [
        "society"
      ],
      "importance": 0.4,
      "description": "The Tokugawa shogun's capital Edo grows past an estimated one million people by the early eighteenth century, among the largest cities in the world alongside Beijing, roughly half of them samurai households and retainers drawn by the alternate- attendance system and half townspeople. The start is an estimate — only commoners were counted — and the interval closes when the city is renamed Tokyo in 1868.\n",
      "citation": "Wikipedia, \"Edo\" (accessed 2026-09-24): population \"surpassed 1 million\" by 1721, \"one of the largest cities in the world at the time, along with Beijing\"; imperial edict renaming Edo \"Tokyo\" issued 3 September 1868 (Wikipedia, \"Edo\"; Wikidata Q11134494). Roughly half warrior class: nihombashi-tokyo.com history page (accessed 2026-09-24). UNVERIFIED: the 1721 townspeople census figure and a scholarly source (e.g. McClain, Merriman & Ugawa eds., Edo and Paris, 1994) were not confirmed live.\n"
    },
    {
      "id": "french-revolution",
      "label": "French Revolution",
      "kind": "period",
      "tMin": 226.0,
      "tMax": 236.0,
      "tags": [
        "society"
      ],
      "importance": 0.65,
      "description": "From the meeting of the Estates-General in May 1789 and the storming of the Bastille that July, revolution overturns France's absolute monarchy, abolishes it in 1792 and executes Louis XVI in 1793, spreading ideas of popular sovereignty and the rights of man across Europe. The period closes with Napoleon Bonaparte's coup of 18 Brumaire, 9 November 1799.\n",
      "citation": "Wikipedia, \"French Revolution\" (accessed 2026-09-24): began with the Estates General of 1789, ended with the Coup of 18 Brumaire, 9 November 1799; monarchy abolished 1792, Louis XVI executed 1793. Estates-General opened 5 May 1789: Château de Versailles, \"Versailles at the heart of the French Revolution, 1789\"; Encyclopaedia Britannica, \"Estates-General.\" Bastille 14 July 1789: World History Encyclopedia, \"Storming of the Bastille.\"\n"
    },
    {
      "id": "british-colonisation-australia",
      "label": "British colonisation of Australia",
      "kind": "moment",
      "tMin": 237.0,
      "tMax": 238.0,
      "t": 237.0,
      "tags": [
        "society"
      ],
      "importance": 0.5,
      "description": "The British First Fleet, eleven ships carrying convicts, marines and officials, arrives at Port Jackson on 26 January 1788, founding the first European colony in Australia and beginning permanent British settlement of a continent already inhabited by Aboriginal and Torres Strait Islander peoples for tens of thousands of years. A smallpox epidemic in April 1789 killed about half the Aboriginal population of the Sydney region within a year of the colony's founding, one of the earliest and starkest instances of the disease and frontier violence that sharply reduced Aboriginal populations across the continent over the following century.\n",
      "citation": "Wikipedia, \"History of Australia (1788-1850)\" (accessed 2026-09-17): First Fleet departs Portsmouth 13 May 1787, arrives at Port Jackson 26 January 1788, colony formally proclaimed 7 February 1788; smallpox outbreak of April 1789 killed about half the Aboriginal population of the Sydney region.\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "migration",
        "origin": {
          "lat": 50.8,
          "lon": -1.1
        },
        "destination": {
          "lat": -33.85,
          "lon": 151.2
        },
        "established": 237.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 238.0
          }
        ]
      }
    },
    {
      "id": "laki-eruption",
      "label": "Laki fissure eruption",
      "kind": "period",
      "tMin": 240.9,
      "tMax": 241.56,
      "tags": [
        "catastrophe",
        "earth-climate"
      ],
      "importance": 0.45,
      "description": "For eight months from 8 June 1783 the Laki fissure in southern Iceland pours out one of the largest basaltic lava flows in historic times and vast volumes of sulphur dioxide and fluorine, spreading a sulphurous haze across Europe. In the famine that followed, livestock losses and fluorine poisoning killed some 20-25% of Iceland's population.\n",
      "citation": "Thordarson, T. & Self, S. (1993). \"The Laki (Skaftár Fires) and Grímsvötn eruptions in 1783-1785.\" Bulletin of Volcanology, 55, 233-263, doi:10.1007/BF00624353 — eight months, 1783-1784, 14.7 +/- 1.0 km3 of lava. Start 8 June 1783, end February 1784, and 20-25% Icelandic mortality: Oregon State University Volcano World, \"Laki, Iceland - 1783\" (accessed 2026-09-24). End date taken as 7 February 1784; the day is UNVERIFIED (month confirmed).\n"
    },
    {
      "id": "american-revolution",
      "label": "American Revolution",
      "kind": "period",
      "tMin": 242.0,
      "tMax": 250.0,
      "tags": [
        "society"
      ],
      "importance": 0.6,
      "description": "Thirteen British colonies in North America go to war with Britain from the fighting at Lexington and Concord in April 1775, declare independence on 4 July 1776, and win recognition as the United States in the Treaty of Paris of September 1783, after French intervention helped force the British surrender at Yorktown in 1781.\n",
      "citation": "US National Park Service, \"Timeline of the Revolution\" (nps.gov/subjects/ americanrevolution/timeline.htm, accessed 2026-09-24); American Battlefield Trust, \"American Revolution Timeline.\" Lexington and Concord 19 April 1775; Declaration of Independence 4 July 1776; Yorktown 1781; Treaty of Paris 3 September 1783.\n"
    },
    {
      "id": "lisbon-earthquake-1755",
      "label": "Lisbon earthquake, tsunami and fire",
      "kind": "moment",
      "tMin": 270.0,
      "tMax": 270.0,
      "t": 270.0,
      "tags": [
        "catastrophe",
        "earth-climate"
      ],
      "importance": 0.45,
      "description": "On the morning of 1 November 1755 a great offshore earthquake, estimated at magnitude 8.5-9.0, wrecks Lisbon; a tsunami follows about forty minutes later and fires burn for five days. Estimates of the dead range widely, commonly 30,000-50,000 in Lisbon and more across Portugal, Spain and Morocco, and the disaster became a touchstone of Enlightenment debate and early seismology.\n",
      "citation": "Chester, D.K. (2001). \"The 1755 Lisbon earthquake.\" Progress in Physical Geography, 25(3), 363-383, doi:10.1177/030913330102500304 — affected ~800,000 km2, \"killed up to 100,000 people.\" Date (1 November 1755, ~09:40 local), magnitude range, tsunami ~40 min after the shock, five-day fire and 30,000-40,000 Lisbon dead (after Á. Pereira 2009): Wikipedia, \"1755 Lisbon earthquake\" (accessed 2026-09-24).\n"
    },
    {
      "id": "transatlantic-slave-trade",
      "label": "Transatlantic slave trade",
      "kind": "period",
      "tMin": 137.0,
      "tMax": 450.0,
      "tags": [
        "society"
      ],
      "importance": 0.6,
      "description": "From Portugal's 1575 colonisation of Angola, and decisively after the Portuguese-Brazilian recapture of Luanda from the Dutch in 1648, European traders and colonial powers force millions of captive West and Central Africans onto ships bound for the Americas to work as forced labour, mostly on plantations and in mines. Of an estimated 12.75 million people loaded onto slave ships over more than three centuries, up to 2 million die during the Middle Passage; Portuguese Brazil ultimately receives the largest single share, roughly 5.5 million people.\n",
      "citation": "Wikipedia, \"Atlantic slave trade\" (accessed 2026-09-17): ~12.75 million Africans loaded onto slave ships, up to 2 million died in the Middle Passage. Wikipedia, \"Slavery in Brazil\" (accessed 2026-09-17): approximately 5.5 million enslaved Africans brought to Brazil between 1540 and the 1860s, out of an estimated 12 million transported to the Americas overall. Heywood, L.M. & Thornton, J.K. (2007). Central Africans, Atlantic Creoles, and the Foundation of the Americas, 1585-1660. Cambridge University Press (Portugal's 1575 colonisation of Angola/founding of Luanda). Alencastro, L.F. de (2018). The Trade in the Living: The Formation of Brazil in the South Atlantic, Sixteenth to Seventeenth Centuries. SUNY Press (the 1648 Portuguese-Brazilian recapture of Luanda from the Dutch securing the Angola-Brazil slave axis). Borucki, A., Eltis, D. & Wheat, D. (2015). \"Atlantic History and the Slave Trade to Spanish America.\" American Historical Review, 120(2), 433-461. doi:10.1093/ahr/120.2.433 (the 1525 Sao Tome-to-Hispaniola voyage, the first transatlantic slave voyage, was Caribbean-bound and unrelated to this Angola-Brazil route).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "migration",
        "origin": {
          "lat": -8.8,
          "lon": 13.2
        },
        "destination": {
          "lat": -13.0,
          "lon": -38.5
        },
        "established": 377.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 450.0
          }
        ]
      }
    },
    {
      "id": "newcomen-steam-engine",
      "label": "Newcomen's atmospheric steam engine",
      "kind": "moment",
      "tMin": 312.0,
      "tMax": 314.0,
      "t": 313.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.55,
      "description": "Thomas Newcomen builds the first practical atmospheric steam engine, pumping water from a flooded coalworks in the English West Midlands — the direct mechanical ancestor of the engines that later power the Industrial Revolution. Only the approximate year, not an exact date, is recorded.\n",
      "citation": "Wikipedia, \"Thomas Newcomen\" (accessed 2026-09-14). Dated \"around 1712.\" UNVERIFIED beyond Wikipedia — not cross-checked against a primary engineering- history source (e.g. the Newcomen Society).\n"
    },
    {
      "id": "newton-principia",
      "label": "Newton publishes the Principia",
      "kind": "moment",
      "tMin": 338.0,
      "tMax": 338.0,
      "t": 338.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.7,
      "description": "Isaac Newton's Philosophiae Naturalis Principia Mathematica appears in July 1687, formulating the laws of motion and universal gravitation and unifying terrestrial and celestial mechanics under one mathematical framework — a foundation for classical physics for the following two centuries.\n",
      "citation": "Wikipedia, \"Philosophiae Naturalis Principia Mathematica\" (accessed 2026-09-14). Royal Society authorised publication 30 June 1686; printed July 1687.\n"
    },
    {
      "id": "columbian-exchange",
      "label": "Columbian Exchange begins",
      "kind": "period",
      "tMin": 225.0,
      "tMax": 533.0,
      "tags": [
        "society",
        "life"
      ],
      "importance": 0.7,
      "description": "Following Columbus's 1492 landfall in the Caribbean, plants, animals, diseases and people begin moving between the Americas and Afro-Eurasia for the first time since the continents separated, reshaping diets, ecosystems and demographics on every continent. On Hispaniola, Spanish colonisation dispossesses and enslaves the Indigenous Taino under the encomienda forced-labour system; combined with introduced disease and violence, this drives an estimated 80-90% collapse of the Taino population within three decades. The interval's end (1800 CE) is a curatorial round number marking the close of the period of most intense early-modern transfer, not a literature-defined boundary.\n",
      "citation": "Wikipedia, \"Columbian exchange\" (accessed 2026-09-14). Conventionally named after Crosby, A.W. (1972). The Columbian Exchange: Biological and Cultural Consequences of 1492. Greenwood Press (title/author/year only; not independently verified this session). Wikipedia, \"Santo Domingo\" (accessed 2026-09-17): founded 5 August 1496, the oldest continuously inhabited European-established settlement in the Americas. Stannard, D.E. (1992). American Holocaust: Columbus and the Conquest of the New World. Oxford University Press. Resendez, A. (2016). The Other Slavery: The Uncovered Story of Indian Enslavement in America. Houghton Mifflin Harcourt (encomienda forced labour and enslavement as major, non-secondary co-drivers of Indigenous population collapse, alongside disease). Fernandes, D.M. et al. (2021). \"A genetic history of the pre-contact Caribbean.\" Nature, 590, 103-110. doi:10.1038/s41586-020-03053-2 (pre-1492 Hispaniola held a settled Indigenous Taino population).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "migration",
        "origin": {
          "lat": 37.2,
          "lon": -6.9
        },
        "destination": {
          "lat": 18.5,
          "lon": -70.0
        },
        "established": 529.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 533.0
          }
        ]
      }
    },
    {
      "id": "ming-qing-transition",
      "label": "Fall of the Ming, Qing take Beijing",
      "kind": "moment",
      "tMin": 381.0,
      "tMax": 381.0,
      "t": 381.0,
      "tags": [
        "society"
      ],
      "importance": 0.4,
      "description": "Li Zicheng's rebel army takes Beijing in April 1644 and the last Ming emperor, Chongzhen, hangs himself. The Ming general Wu Sangui lets the Manchus through the Great Wall at Shanhai Pass; together they defeat Li, and in June the Manchu Qing dynasty occupies Beijing, going on to conquer the rest of China.\n",
      "citation": "Via Wikipedia \"Transition from Ming to Qing\" and \"Battle of Shanhai Pass\" (searched 2026-09-24): Beijing falls to Li Zicheng, 24-25 April 1644, Chongzhen Emperor's suicide; Qing and Wu Sangui enter Beijing, 6 June 1644.\n"
    },
    {
      "id": "dutch-golden-age-voc",
      "label": "Amsterdam's Dutch Golden Age",
      "kind": "period",
      "tMin": 353.0,
      "tMax": 437.0,
      "tags": [
        "society"
      ],
      "importance": 0.5,
      "description": "Amsterdam becomes Europe's foremost trading hub and, for a time, the wealthiest city in the Western world, powered by the Dutch East India Company (VOC), one of the world's first joint-stock companies: its shares, publicly traded from 1602, helped give Amsterdam what is often called the world's oldest modern securities market, and by 1669 the VOC had grown into a private commercial empire of some 50,000 employees, over 150 merchant ships and 40 warships.\n",
      "citation": "Wikipedia, \"Dutch Golden Age\" (accessed 2026-09-15): the era spans 1588-1672; Amsterdam \"one of the most important ports and commercial centres in the world by 1630.\" Wikipedia, \"Dutch East India Company\" (accessed 2026-09-15): VOC \"one of the first joint-stock companies in the world,\" its shares traded in open secondary markets \"one of which became the Amsterdam Stock Exchange\"; by 1669, \"over 150 merchant ships, 40 warships, 50,000 employees.\" Wikipedia, \"Euronext Amsterdam\" (accessed 2026-09-15): the Amsterdam exchange \"is considered the oldest 'modern' securities market in the world.\" Wikipedia, \"Amsterdam\" (accessed 2026-09-15): the 17th-century Golden Age city \"became the wealthiest city in the Western world.\"\n"
    },
    {
      "id": "galileo-telescope",
      "label": "Galileo's telescopic discoveries",
      "kind": "moment",
      "tMin": 415.0,
      "tMax": 416.0,
      "t": 415.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.5,
      "description": "Galileo Galilei builds his own telescope in 1609 and, observing in January 1610, discovers four moons orbiting Jupiter — direct evidence that not everything in the sky orbits Earth. He publishes the findings in Sidereus Nuncius the following March.\n",
      "citation": "Wikipedia, \"Galileo Galilei\" (accessed 2026-09-14). Telescope built 1609; Jupiter observations 7-15 January 1610; Sidereus Nuncius published March 1610.\n"
    },
    {
      "id": "russian-conquest-of-siberia",
      "label": "Russian conquest of Siberia",
      "kind": "period",
      "tMin": 386.0,
      "tMax": 444.0,
      "tags": [
        "society"
      ],
      "importance": 0.45,
      "description": "A Cossack force under Yermak Timofeyevich invades the Khanate of Sibir in 1581, opening a rapid Russian conquest and colonisation of Siberia's forests and tundra; Russian forces reach the Pacific coast by 1639, having subdued and imposed tribute on numerous indigenous Siberian peoples (among them the Khanty, Mansi, Yakut and Evenki) along the way. Russian and Cossack settlement, fur trading, and, from the 19th century, agricultural colonisation follow the same route east, reshaping Siberia's demographic and political map.\n",
      "citation": "Wikipedia, \"Russian conquest of Siberia\" (accessed 2026-09-17): Yermak Timofeyevich's Cossack force invades the Khanate of Sibir in July 1581; Russians reach the Pacific Ocean in 1639 (citing Nationalencyklopedin).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "migration",
        "origin": {
          "lat": 55.75,
          "lon": 37.6
        },
        "destination": {
          "lat": 59.3,
          "lon": 143.2
        },
        "established": 386.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 444.0
          }
        ]
      }
    },
    {
      "id": "ottoman-greatest-extent",
      "label": "Ottoman Empire at its greatest extent",
      "kind": "period",
      "tMin": 422.0,
      "tMax": 435.0,
      "tags": [
        "society"
      ],
      "importance": 0.35,
      "description": "The Treaty of Constantinople of 1590 ends a twelve-year war with Safavid Iran and cedes Georgia, Armenia, Azerbaijan and western Iran to the Ottomans, their widest eastern border. Shah Abbas I begins retaking the lands in 1603. Measured instead by reach into Europe, the empire's high-water mark was the siege of Vienna in 1683.\n",
      "citation": "Via Wikipedia \"Treaty of Constantinople (1590)\" and \"Safavid capture of Tabriz (1603)\" (searched 2026-09-24): treaty signed 21 March 1590, Georgia, Azerbaijan, Armenia and western Iran under Ottoman rule; Tabriz retaken 21 October 1603.\n"
    },
    {
      "id": "battle-of-tondibi",
      "label": "Morocco defeats Songhai at Tondibi",
      "kind": "moment",
      "tMin": 434.0,
      "tMax": 434.0,
      "t": 434.0,
      "tags": [
        "society"
      ],
      "importance": 0.35,
      "description": "A Moroccan army of about 4,000 under Judar Pasha, armed with arquebuses and cannon, crosses the Sahara and routs a far larger Songhai army at Tondibi, near Gao, on 13 March 1591. Gao, Timbuktu and Djenne are taken, and the Songhai Empire, West Africa's largest state, never recovers.\n",
      "citation": "Via Wikipedia \"Battle of Tondibi\" and \"Moroccan invasion of the Songhai Empire\" (searched 2026-09-24): battle 13 March 1591; Judar Pasha against Askia Ishaq II; Gao, Timbuktu and Djenne seized.\n"
    },
    {
      "id": "little-ice-age",
      "label": "Little Ice Age",
      "kind": "period",
      "tMin": 175.0,
      "tMax": 725.0,
      "tags": [
        "earth-climate",
        "society"
      ],
      "importance": 0.55,
      "description": "A multi-century interval of cooler Northern Hemisphere climate and advancing mountain glaciers, conventionally placed c. 1300-1850; its bounds are contested, with the coldest summers concentrated c. 1570-1900. It spans the Maunder Minimum of near-absent sunspots (1645-1715) and the Thames frost fairs held on the frozen river in London between 1608 and 1814, though the Thames did not freeze more often during the Maunder Minimum itself.\n",
      "citation": "Matthews, J.A. & Briffa, K.R. (2005). \"The 'Little Ice Age': re-evaluation of an evolving concept.\" Geografiska Annaler: Series A, Physical Geography, 87A(1), 17-36, doi:10.1111/j.0435-3676.2005.00242.x — glacierization c. AD 1300-1950 (European Alps), \"Little Ice Age\" climate c. AD 1570-1900. Eddy, J.A. (1976). \"The Maunder Minimum.\" Science, 192(4245), 1189-1202 — sunspot minimum 1645-1715. Owens, M.J. et al. (2017), \"The Maunder minimum and the Little Ice Age: an update from recent reconstructions and climate simulations,\" Journal of Space Weather and Space Climate, 7, A33 — no increase in Thames freezings during the Maunder Minimum (volume/article number UNVERIFIED). Frost fairs 1608 and February 1814 (last): London Museum, \"Frost fairs: festivities on a frozen River Thames\" (accessed 2026-09-24).\n"
    },
    {
      "id": "spanish-conquest-of-inca",
      "label": "Spanish conquest of the Inca Empire",
      "kind": "period",
      "tMin": 453.0,
      "tMax": 493.0,
      "tags": [
        "society"
      ],
      "importance": 0.45,
      "description": "Francisco Pizarro's small force captures the Inca emperor Atahualpa at Cajamarca in November 1532 and executes him the following year. Inca resistance continues from the Neo-Inca State at Vilcabamba until 1572, when the Spanish take it and execute the last Inca ruler, Tupac Amaru.\n",
      "citation": "Via Wikipedia \"Spanish conquest of the Inca Empire\" and \"Neo-Inca State\" (searched 2026-09-24): Atahualpa captured at Cajamarca, 1532, killed 29 August 1533; Vilcabamba taken and Tupac Amaru executed in Cusco, 1572.\n"
    },
    {
      "id": "copernicus-heliocentrism",
      "label": "Copernicus publishes heliocentrism",
      "kind": "moment",
      "tMin": 482.0,
      "tMax": 482.0,
      "t": 482.0,
      "tags": [
        "science-technology"
      ],
      "importance": 0.55,
      "description": "Nicolaus Copernicus's De revolutionibus orbium coelestium is printed in Nuremberg shortly before his death, arguing that Earth and the other planets orbit the Sun — the founding text of the shift away from an Earth-centred cosmos that drives the wider scientific revolution.\n",
      "citation": "Wikipedia, \"De revolutionibus orbium coelestium\" (accessed 2026-09-14). Publication year 1543; only the year, not an exact day, is recorded.\n"
    },
    {
      "id": "fall-of-tenochtitlan",
      "label": "Fall of Tenochtitlan",
      "kind": "moment",
      "tMin": 504.0,
      "tMax": 504.0,
      "t": 504.0,
      "tags": [
        "society",
        "catastrophe"
      ],
      "importance": 0.45,
      "description": "Spanish forces under Hernan Cortes, with tens of thousands of Indigenous allies led by the Tlaxcalans, besiege the smallpox-stricken Aztec capital from May 1521. Its last ruler, Cuauhtemoc, is captured on 13 August, and the city's surrender ends the Aztec Empire.\n",
      "citation": "Via Wikipedia \"Fall of Tenochtitlan\" and \"Spanish conquest of the Aztec Empire\" (searched 2026-09-24): siege 26 May to 13 August 1521; Tlaxcalan and other native allies; smallpox epidemic in the city; Cuauhtemoc captured.\n"
    },
    {
      "id": "fall-of-constantinople",
      "label": "Fall of Constantinople",
      "kind": "moment",
      "tMin": 572.0,
      "tMax": 572.0,
      "t": 572.0,
      "tags": [
        "society"
      ],
      "importance": 0.55,
      "description": "Ottoman forces under Sultan Mehmed II take Constantinople on 29 May 1453 after a 53-day siege in which cannon batter the city's land walls. The last emperor, Constantine XI, dies in the fighting; the Byzantine Empire, the last continuation of the Roman Empire, ends, and the city becomes the Ottoman capital.\n",
      "citation": "Via Wikipedia \"Fall of Constantinople\" (searched 2026-09-24): captured 29 May 1453 after a siege begun 6 April; Mehmed II against Constantine XI Palaiologos, who died in the fall of the city.\n"
    },
    {
      "id": "gutenberg-printing-press",
      "label": "Gutenberg's printing press",
      "kind": "period",
      "tMin": 570.0,
      "tMax": 577.0,
      "tags": [
        "science-technology",
        "society"
      ],
      "importance": 0.7,
      "description": "Johannes Gutenberg develops a movable-type printing press in Mainz, combining reusable metal type, oil-based ink and a wooden press adapted from a wine press. He is documented back in Mainz taking out a loan, plausibly for press equipment, by 1448; the press is in operation by 1450, and the 42-line Bible is being printed by 1455. An earlier, unconfirmed tradition places experimental trials in Strasbourg around 1440, but the surviving record does not establish what work he was actually doing there, so the interval here starts at the better-documented 1448 Mainz loan rather than the Strasbourg claim.\n",
      "citation": "Wikipedia, \"Johannes Gutenberg\" and \"Printing press\" (accessed 2026-09-14). Merges two independently drafted candidate events for the same milestone (workshop- founding vs. operational vs. Bible- printing framings). UNVERIFIED beyond Wikipedia: the ~1440 Strasbourg claim is flagged uncertain in the source itself and was not used to set t_max.\n"
    },
    {
      "id": "black-death",
      "label": "Black Death pandemic",
      "kind": "period",
      "tMin": 672.0,
      "tMax": 679.0,
      "tags": [
        "catastrophe",
        "society"
      ],
      "importance": 0.55,
      "description": "The Black Death, a plague pandemic carried along trade routes from Central/East Asia, sweeps Europe, Western Asia and North Africa between 1346 and 1353, killing an estimated 25-50 million people (some Eurasia-wide estimates run to 75-200 million) — 30-60% of Europe's population in a few years. Its demographic shock reshaped labour markets, land tenure and social structure across the continent for generations afterward.\n",
      "citation": "Via Wikipedia \"Black Death\": 1346-1353 across Europe, Western Asia and North Africa; death toll 25-50M (Eurasia-wide estimates 75-200M); European mortality 30-60%. Underlying demographic studies not independently fetched.\n"
    },
    {
      "id": "mongol-empire",
      "label": "Mongol Empire spans Eurasia",
      "kind": "period",
      "tMin": 657.0,
      "tMax": 819.0,
      "tags": [
        "society"
      ],
      "importance": 0.45,
      "description": "Genghis Khan is proclaimed khan of the united Mongol tribes in 1206, founding an empire that becomes the largest contiguous land empire in history, spanning the Pacific to Eastern Europe at its territorial peak around 1294. The politically unified empire itself fragmented after Möngke Khan's death in 1259, splitting into four khanates; the interval used here runs to 1368, when the last successor state, the Yuan dynasty, fell to Ming forces — a \"founding to final dissolution\" span, broader than the shorter life of the empire as a single unified polity.\n",
      "citation": "Via Wikipedia \"Mongol Empire\": proclaimed 1206; Möngke Khan's death and fragmentation, 1259; territorial peak ~23.5M km^2 (1294); Yuan dynasty fall, 1368.\n"
    },
    {
      "id": "aotearoa-arrival",
      "label": "Arrival in Aotearoa New Zealand",
      "kind": "moment",
      "tMin": 725.0,
      "tMax": 775.0,
      "t": 745.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.5,
      "description": "Aotearoa New Zealand is the last major landmass settled by humans. Radiocarbon dating of rat-gnawed seeds and Pacific rat (kiore) bone -- a reliable proxy for human arrival, since the rat travelled only with Polynesian voyagers -- points to settlement around AD 1280. A synthesis of archaeological, genealogical and genetic evidence points to the same event: a single mass migration of Polynesian settlers in the early 14th century, rather than the sporadic earlier arrivals some older accounts proposed.\n",
      "citation": "Wilmshurst, J.M., Anderson, A.J., Higham, T.F.G. & Worthy, T.H. (2008). \"Dating the late prehistoric dispersal of Polynesians to New Zealand using the commensal Pacific rat.\" PNAS, 105(22), 7676-7680. doi:10.1073/pnas.0801507105 (rat-bone radiocarbon dating, ~AD 1280). Walter, R., Buckley, H., Jacomb, C. & Matisoo-Smith, E. (2017). \"Mass Migration and the Polynesian Settlement of New Zealand.\" Journal of World Prehistory, 30, 351-376. doi:10.1007/s10963-017-9110-y (single mass-migration event, early 14th century).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": -20.0,
          "lon": -157.0
        },
        "destination": {
          "lat": -41.0,
          "lon": 173.0
        },
        "established": 745.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 775.0
          }
        ]
      }
    },
    {
      "id": "thule-arctic-expansion",
      "label": "Thule expansion across the Arctic",
      "kind": "period",
      "tMin": 725.0,
      "tMax": 800.0,
      "tags": [
        "human-origins",
        "society"
      ],
      "importance": 0.45,
      "description": "The Thule culture, ancestral to modern Inuit, emerges among Bering Strait maritime hunters in coastal Alaska and expands rapidly eastward across the Canadian Arctic archipelago to Greenland, carrying skin boats, dog sleds and toggling harpoons adapted to open-water whaling. Ancient-genome analysis shows Thule people almost completely replaced, with little or no admixture, the earlier Palaeo-Inuit Dorset culture, which had occupied the eastern Arctic for the previous two millennia and had vanished within a few centuries of Thule contact.\n",
      "citation": "Friesen, T.M. & Arnold, C.D. (2008). \"The Timing of the Thule Migration: New Dates from the Western Canadian Arctic.\" American Antiquity, 73(3), 527-538. doi:10.1017/S0002731600046850 (western Canadian Arctic transit corridor sites not occupied before the 13th century AD, refuting an ~1000 CE onset for the eastward migration). Raghavan, M. et al. (2014). \"The Genetic Prehistory of the New World Arctic.\" Science, 345(6200), 1255832. doi:10.1126/science.1255832 (Thule populations largely replace, with no detected Dorset admixture, the earlier Dorset culture across northern Canada and Greenland by about 1300 CE). Wikipedia, \"Thule people\" (accessed 2026-09-17): Thule tradition develops in coastal Alaska by 1000 CE — a claim about the culture's Alaskan origin, not the eastward migration's own start — and expands east across the Canadian Arctic, displacing the Dorset culture by the 13th-15th century.\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "migration",
        "origin": {
          "lat": 68.3,
          "lon": -166.8
        },
        "destination": {
          "lat": 77.5,
          "lon": -69.0
        },
        "established": 725.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 800.0
          }
        ]
      }
    },
    {
      "id": "mongol-sack-of-baghdad",
      "label": "Mongols sack Baghdad",
      "kind": "moment",
      "tMin": 767.0,
      "tMax": 767.0,
      "t": 767.0,
      "tags": [
        "society",
        "catastrophe"
      ],
      "importance": 0.45,
      "description": "A Mongol army under Hulagu, brother of the Great Khan Mongke, besieges Baghdad and takes its surrender in February 1258. The last Abbasid caliph, al-Musta'sim, is executed, the city is sacked and its libraries, including the House of Wisdom, are destroyed, ending the Abbasid Caliphate in Baghdad.\n",
      "citation": "Via Wikipedia \"Siege of Baghdad\" (searched 2026-09-24): siege 29 January to 10 February 1258 by Hulagu's forces; caliph al-Musta'sim put to death; city sacked and the House of Wisdom destroyed.\n"
    },
    {
      "id": "greenland-norse-settlement",
      "label": "Norse settlement of Greenland",
      "kind": "period",
      "tMin": 595.0,
      "tMax": 1045.0,
      "tags": [
        "society"
      ],
      "importance": 0.4,
      "description": "Norse settlers from Iceland, led by Erik the Red, colonise Greenland's south-western coast from around AD 985, founding the Eastern and Western Settlements. Unlike Iceland, the region had no established prior population at the time of Norse arrival: Dorset presence was concentrated far to the north, and Thule Inuit reach and come into contact with the Norse settlement area only later, in the 13th-14th century (thule-arctic-expansion). Cut off from Norway, the settlements disappear by the mid-15th century — the most recent radiocarbon date from the Eastern Settlement is AD 1430 +/-15 years — for reasons still debated among climate change, resource depletion, economic/trade collapse and conflict with expanding Thule Inuit populations.\n",
      "citation": "Arneborg, J. (2012). \"Norse Greenland Dietary Economy ca. AD 980-ca. AD 1450: Introduction.\" Journal of the North Atlantic, Special Volume 3, 1-39. doi:10.3721/037.004.s303. Arneborg, J., Heinemeier, J., Lynnerup, N., Nielsen, H.L., Rud, N. & Sveinbjornsdottir, A.E. (1999). \"Change of Diet of the Greenland Vikings Determined from Stable Carbon Isotope Analysis and 14C Dating of Their Bones.\" Radiocarbon, 41(2), 157-168. doi:10.1017/S0033822200019512 (AD 1430 +/-15 years, most recent radiocarbon date, Eastern Settlement).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": 64.15,
          "lon": -21.9
        },
        "destination": {
          "lat": 60.7,
          "lon": -46.0
        },
        "established": 1040.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 1045.0
          }
        ]
      }
    },
    {
      "id": "angkor-wat-built",
      "label": "Angkor Wat built",
      "kind": "period",
      "tMin": 875.0,
      "tMax": 903.0,
      "tags": [
        "society",
        "science-technology"
      ],
      "importance": 0.55,
      "description": "King Suryavarman II of the Khmer Empire commissions Angkor Wat, in present-day Cambodia, as his state temple, dedicated to Vishnu. Construction runs through his reign, completed close to his death around 1150 — the largest religious monument in the world, surrounded by a moat over 5 km in perimeter.\n",
      "citation": "Wikipedia, \"Angkor Wat\" (accessed 2026-09-15): construction 1113-1150, building work usually dated 1122-1150; Suryavarman II reigned 1113-c.1150; moat 190 m wide, over 5 km in perimeter.\n"
    },
    {
      "id": "east-polynesia-arrival",
      "label": "Arrival in East Polynesia",
      "kind": "moment",
      "tMin": 905.0,
      "tMax": 1125.0,
      "t": 953.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.5,
      "description": "High-precision radiocarbon dating shows central East Polynesia (the Society Islands) was first settled in a short window around AD 1025-1120 -- several centuries later than older, less precise chronologies had suggested -- with a second, rapid dispersal pulse around AD 1190-1290 then settling the remaining East Polynesian islands, including Hawaii, Rapa Nui (Easter Island) and Aotearoa New Zealand (aotearoa-arrival), within about a century. This short chronology is not fully settled: other reconstructions, combining sea-level, palaeoenvironmental and genomic evidence, argue for an earlier, more incremental settlement from around AD 900.\n",
      "citation": "Wilmshurst, J.M., Hunt, T.L., Lipo, C.P. & Anderson, A.J. (2011). \"High-precision radiocarbon dating shows recent and rapid initial human colonization of East Polynesia.\" PNAS, 108(5), 1815-1820. doi:10.1073/pnas.1015876108. Central East Polynesia settled A.D. ~1025-1120; remaining islands reached in a single dispersal pulse A.D. ~1190-1290. Sear, D.A. et al. (2020). \"Human settlement of East Polynesia earlier, incremental, and coincident with prolonged South Pacific drought.\" PNAS, 117(16), 8813-8819. doi:10.1073/pnas.1920975117 (settlement from ~AD 900). Ioannidis, A.G. et al. (2021). \"Paths and timings of the peopling of Polynesia inferred from genomic networks.\" Nature, 597, 522-526. doi:10.1038/s41586-021-03902-8.\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": -14.0,
          "lon": -172.0
        },
        "destination": {
          "lat": -17.0,
          "lon": -150.0
        },
        "established": 953.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 1125.0
          }
        ]
      }
    },
    {
      "id": "norse-north-atlantic-settlement",
      "label": "Norse settlement of Iceland",
      "kind": "moment",
      "tMin": 1145.0,
      "tMax": 1165.0,
      "t": 1148.0,
      "tags": [
        "society"
      ],
      "importance": 0.4,
      "description": "Norse seafarers from Norway, together with enslaved and free Gaelic people from Ireland and Scotland whom they captured or brought with them, settle Iceland, previously uninhabited (medieval sources describe earlier Irish hermits, the papar, but this is archaeologically unproven), from around AD 860, with a tephra-dated landnam of AD 877 +/-1 — traditionally dated to AD 874 on saga evidence (Ingolfr Arnarson's landnam at Reykjavik). Iceland's founding population is genetically only around 56% Norse, with a majority-Gaelic maternal line, reflecting this coerced component.\n",
      "citation": "Schmid, M.M.E., Dugmore, A.J., Vesteinsson, O. & Newton, A.J. (2017). \"Tephra isochrons and chronologies of colonisation.\" Quaternary Geochronology, 40, 56-66. doi:10.1016/j.quageo.2016.08.002 (Landnam tephra dated AD 877 +/-1). Vesteinsson, O. & McGovern, T.H. (2012). \"The Peopling of Iceland.\" Norwegian Archaeological Review, 45(2), 206-218. doi:10.1080/00293652.2012.721792. Ebenesersdottir, S.S. et al. (2018). \"Ancient genomes from Iceland reveal the making of a human population.\" Science, 360(6392), 1028-1032. doi:10.1126/science.aar2625 (founding population ~56% Norse ancestry; ~62% Gaelic mtDNA line).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": 61.0,
          "lon": 5.5
        },
        "destination": {
          "lat": 64.15,
          "lon": -21.9
        },
        "established": 1148.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 1165.0
          }
        ]
      }
    },
    {
      "id": "classic-maya-collapse",
      "label": "Classic Maya collapse",
      "kind": "period",
      "tMin": 1075.0,
      "tMax": 1275.0,
      "tags": [
        "society",
        "catastrophe"
      ],
      "importance": 0.5,
      "description": "Across the southern Maya lowlands, the great Classic cities stop raising dated monuments and lose most of their people between the late 8th and 10th centuries; Tikal's last dated monument is from 869. Repeated droughts, warfare between city states, and the failure of divine kingship are all proposed causes and are debated.\n",
      "citation": "Via Wikipedia \"Classic Maya collapse\" and \"Stela 11\" of Tikal, Long Count 10.2.0.0.0, 15 August 869 (accessed 2026-09-25). Evans, N.P. et al. (2018). \"Quantification of drought during the collapse of the classic Maya civilization.\" Science, 361(6401), 498-501. UNVERIFIED: the 750-950 bracket is the conventional span, not a single source's figure.\n"
    },
    {
      "id": "an-lushan-rebellion",
      "label": "An Lushan Rebellion",
      "kind": "period",
      "tMin": 1262.0,
      "tMax": 1270.0,
      "tags": [
        "society",
        "catastrophe"
      ],
      "importance": 0.4,
      "description": "The frontier general An Lushan rebels against the Tang in 755 and takes both capitals, Luoyang and Chang'an. The war lasts until 763, ends the Tang golden age and begins the dynasty's long decline; in 763 the Tibetan Empire, exploiting the turmoil, briefly occupies Chang'an.\n",
      "citation": "Via Wikipedia \"An Lushan rebellion\" and \"Chang'an\" (searched 2026-09-24): rebellion 755-763, ending with Shi Chaoyi's defeat; Chang'an occupied by the Tibetan Empire for about 15 days in 763.\n"
    },
    {
      "id": "umayyad-greatest-extent",
      "label": "Umayyad Caliphate at its greatest extent",
      "kind": "period",
      "tMin": 1285.0,
      "tMax": 1307.0,
      "tags": [
        "society"
      ],
      "importance": 0.4,
      "description": "With the conquest of the Iberian Peninsula complete by 718, and Sindh and much of Transoxiana taken under al-Walid I, the Umayyad Caliphate ruled from the Atlantic to the Indus, the largest state the world had yet seen. The Berber Revolt of 740 cost it most of the Maghreb, and the Abbasid Revolution overthrew the dynasty in 750.\n",
      "citation": "Via Wikipedia \"Umayyad Caliphate\", \"Muslim conquest of the Iberian Peninsula\" and \"Berber Revolt\" (searched 2026-09-24): conquest of Hispania 711-718; North Africa, Hispania, Transoxiana and Sindh conquered under al-Walid I (705-715); Berber Revolt from 740, the Maghreb beyond Ifriqiya never recovered.\n"
    },
    {
      "id": "tikal-late-classic",
      "label": "Tikal at its Late Classic height",
      "kind": "period",
      "tMin": 1259.0,
      "tMax": 1343.0,
      "tags": [
        "society"
      ],
      "importance": 0.5,
      "description": "Under Jasaw Chan K'awiil (acceded 682) and his son Yik'in Chan K'awiil (734-c.766), Tikal becomes one of the largest Classic Maya cities, with tens of thousands of people in the rainforest of present-day Guatemala living from rain-fed reservoirs. Its tallest temple-pyramids are built in this era, among them Temple I, Jasaw Chan K'awiil's funerary temple, completed by his son.\n",
      "citation": "Via Wikipedia \"Tikal\", \"Tikal Temple I\", \"Jasaw Chan K'awiil I\" and \"Yik'in Chan K'awiil\" (accessed 2026-09-25): Jasaw Chan K'awiil I entombed in Temple I c. 734; Yik'in Chan K'awiil acceded 8 December 734, ruled to 766 and completed Temple I; Jasaw Chan K'awiil I acceded 3 May 682.\n"
    },
    {
      "id": "fall-of-western-roman-empire",
      "label": "Fall of the Western Roman Empire",
      "kind": "moment",
      "tMin": 1549.0,
      "tMax": 1549.0,
      "t": 1549.0,
      "tags": [
        "society"
      ],
      "importance": 0.55,
      "description": "Odoacer, a Germanic general of the Roman army in Italy, deposes the boy emperor Romulus Augustulus in September 476 and rules as king of Italy rather than naming a new emperor. The date is a convention for a long decline, and the eastern empire continues from Constantinople for almost another thousand years.\n",
      "citation": "Via Wikipedia \"Fall of the Western Roman Empire\" and \"Romulus Augustulus\" (searched 2026-09-24): Romulus Augustulus deposed by Odoacer, 4 September 476, the date most commonly given for the end of the empire in the west.\n"
    },
    {
      "id": "end-of-han-dynasty",
      "label": "End of the Han dynasty",
      "kind": "moment",
      "tMin": 1805.0,
      "tMax": 1805.0,
      "t": 1805.0,
      "tags": [
        "society"
      ],
      "importance": 0.4,
      "description": "Cao Pi, son of the warlord Cao Cao, forces the last Han emperor, Xian, to abdicate in his favour in December 220 and proclaims the state of Wei. Liu Bei proclaims himself emperor of Shu Han in 221 and Sun Quan breaks with Wei as king of Wu in 222 (emperor from 229), dividing China into the Three Kingdoms.\n",
      "citation": "Via Wikipedia \"End of the Han dynasty\", \"Emperor Xian of Han\" and \"Sun Quan\" (searched 2026-09-24): abdication to Cao Pi, 11 December 220; Liu Bei emperor of Shu Han, 221; Sun Quan breaks with Wei as king of Wu, 222, and declares himself emperor, 229.\n"
    },
    {
      "id": "roman-empire-peak",
      "label": "Roman Empire at its height",
      "kind": "period",
      "tMin": 1845.0,
      "tMax": 1929.0,
      "tags": [
        "society",
        "science-technology"
      ],
      "importance": 0.6,
      "description": "Trajan's reign (AD 98-117) carries the Roman Empire to its greatest territorial extent, about 5 million square kilometres from Britain to Mesopotamia; the Nerva-Antonine \"Five Good Emperors\" who follow, through AD 180, preside over the Pax Romana's most stable and prosperous span. Hadrian's rebuilt Pantheon in Rome, its huge unreinforced-concrete dome the largest built anywhere for the next 1,300 years, is dedicated within this period, around AD 126.\n",
      "citation": "Wikipedia, \"Roman Empire\" (accessed 2026-09-15): territorial peak under Trajan, AD 98-117, ~5,000,000 km^2; Nerva-Antonine dynasty and Pax Romana, AD 96-180. Wikipedia, \"Pantheon, Rome\" (accessed 2026-09-15): present building completed and probably dedicated by Hadrian c. AD 126.\n"
    },
    {
      "id": "madagascar-arrival",
      "label": "Arrival in Madagascar",
      "kind": "moment",
      "tMin": 1175.0,
      "tMax": 2375.0,
      "t": 2075.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.4,
      "description": "Madagascar is among the last major landmasses settled by humans. A critical review of the island's radiocarbon record finds human presence by at least 2000 calibrated years BP, with an earlier, isolated claim of cut-marked megafauna bone pushing possible visits back to roughly 10,500 years ago -- contested, since the species and even the human origin of those cut marks is not established. Definite, continuous colonisation is dated to roughly 1350-1100 years BP. Genomic evidence shows the Malagasy descend from an admixture of Austronesian and Bantu-speaking African settlers; the Austronesian side is linguistically closest to the Barito languages of southeast Borneo, the traditional source region shown here.\n",
      "citation": "Douglass, K. et al. (2019). \"A critical review of radiocarbon dates clarifies the human settlement of Madagascar.\" Quaternary Science Reviews, 221, 105878. doi:10.1016/j.quascirev.2019.105878 (presence by at least 2000 cal BP). Burney, D.A. et al. (2004). \"A chronology for late prehistoric Madagascar.\" Journal of Human Evolution, 47(1-2), 25-63. doi:10.1016/j.jhevol.2004.05.005. Anderson, A. et al. (2018). \"New evidence of megafaunal bone damage indicates late colonization of Madagascar.\" PLOS ONE, 13(10), e0204368. doi:10.1371/journal.pone.0204368 (colonisation 1350-1100 BP; contested >10,500-year-old cut marks). Pierron, D. et al. (2017). \"Genomic landscape of human diversity across Madagascar.\" PNAS, 114(32), E6498-E6506. doi:10.1073/pnas.1704906114 (Austronesian/Bantu admixture).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": -2.5,
          "lon": 115.0
        },
        "destination": {
          "lat": -19.0,
          "lon": 46.5
        },
        "established": 2075.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 2375.0
          }
        ]
      }
    },
    {
      "id": "destruction-of-carthage",
      "label": "Rome destroys Carthage",
      "kind": "moment",
      "tMin": 2171.0,
      "tMax": 2171.0,
      "t": 2171.0,
      "tags": [
        "society",
        "catastrophe"
      ],
      "importance": 0.4,
      "description": "A Roman army under Scipio Aemilianus storms Carthage in spring 146 BC, ending a three-year siege and the Third Punic War. The city is burned and razed, its surviving inhabitants enslaved, and its territory becomes the Roman province of Africa, leaving Rome unrivalled in the western Mediterranean.\n",
      "citation": "Via Wikipedia \"Siege of Carthage (Third Punic War)\" and \"Third Punic War\" (searched 2026-09-24): siege 149 to spring 146 BC; city razed, some 50,000 prisoners enslaved; territory made the province of Africa.\n"
    },
    {
      "id": "qin-unification",
      "label": "Qin dynasty unifies China",
      "kind": "period",
      "tMin": 2231.0,
      "tMax": 2246.0,
      "tags": [
        "society",
        "science-technology"
      ],
      "importance": 0.55,
      "description": "King Zheng of Qin completes the conquest of China's rival Warring States in 221 BC, becoming its first emperor (Qin Shi Huang) and standardising its currency, weights and measures, and writing system across the newly unified territory. His capital, Xianyang, is by tradition ringed by a network of over two hundred palaces across the Wei valley, and needs no defensive wall of its own. The dynasty he founds collapses within four years of his death in 210 BC, falling to rebellion in 206 BC.\n",
      "citation": "Via Wikipedia \"Qin dynasty\" and \"Qin Shi Huang\" (accessed 2026-09-17): unification 221 BC; dynasty ends 206 BC; standardisation of currency, weights/measures and writing; Xianyang \"the only capital city in China that did not require walls to be built around it\"; a network of \"over 200\" palaces linked by covered roads. Primary sources (Sima Qian's Records of the Grand Historian) not independently read.\n"
    },
    {
      "id": "alexander-conquers-persia",
      "label": "Alexander conquers the Persian Empire",
      "kind": "period",
      "tMin": 2355.0,
      "tMax": 2359.0,
      "tags": [
        "society"
      ],
      "importance": 0.5,
      "description": "Alexander of Macedon crosses into Anatolia in 334 BC, defeats the Persian satraps at the Granicus, then Darius III himself at Issus in 333 BC and, decisively, at Gaugamela in 331 BC, and occupies the Persian heartland. Darius is murdered by his own satrap Bessus in 330 BC, ending the Achaemenid Empire, which Alexander carries on to the Indus.\n",
      "citation": "Via Wikipedia \"Battle of the Granicus\", \"Battle of Issus\", \"Battle of Gaugamela\" and \"Darius III\" (searched 2026-09-24): Granicus, May 334 BC, against the satraps of Asia Minor; Issus, November 333 BC; Gaugamela, 1 October 331 BC; Darius killed by Bessus, July 330 BC.\n"
    },
    {
      "id": "periclean-athens",
      "label": "Age of Pericles in Athens",
      "kind": "period",
      "tMin": 2454.0,
      "tMax": 2486.0,
      "tags": [
        "society",
        "science-technology"
      ],
      "importance": 0.55,
      "description": "From his political ascendancy in 461 BC to his death in 429 BC, Pericles dominates Athenian politics and, drawing on the Delian League's treasury, funds the building programme that produces most of the surviving structures on the Acropolis, including the Parthenon (dedicated 438/439 BC, its sculptural decoration finished by 432 BC) and the Propylaea gatehouse (finished 432 BC). This \"Golden Age\" also sees Athenian naval power and direct democracy at their height, shortly before the Peloponnesian War (431-404 BC) begins.\n",
      "citation": "Via Wikipedia \"Pericles\" and \"Parthenon\" (accessed 2026-09-17): Pericles' political dominance 461-429 BC; Parthenon dedicated 438/439 BC, sculptures finished 432 BC; Propylaea finished 432 BC. Primary sources (Thucydides, Plutarch) not independently read.\n"
    },
    {
      "id": "coinage-invented",
      "label": "Coinage invented in Lydia",
      "kind": "moment",
      "tMin": 2585.0,
      "tMax": 2650.0,
      "t": 2625.0,
      "tags": [
        "society",
        "science-technology"
      ],
      "importance": 0.4,
      "description": "Standardized metal coinage — electrum pieces stamped with an issuing authority's mark — first appears in Iron Age Lydia and Ionia in the late 7th century BC, replacing weighed bullion with a portable, trust-based medium of exchange. Alyattes of Lydia is conventionally credited with early state-issued coinage, and his son Croesus (r. c. 560-546 BC) with the first coins of standardized purity; the earliest known inscribed coins come from Ephesus.\n",
      "citation": "Via Wikipedia \"Coin\", drawing on Herodotus, Aristotle and Pollux, plus the Ephesus Artemision hoard; primary/archaeological sources not independently checked.\n"
    },
    {
      "id": "fall-of-nineveh",
      "label": "Fall of Nineveh",
      "kind": "moment",
      "tMin": 2637.0,
      "tMax": 2637.0,
      "t": 2637.0,
      "tags": [
        "society"
      ],
      "importance": 0.35,
      "description": "A coalition of Babylonians under Nabopolassar and Medes under Cyaxares takes Nineveh, the capital of the Neo-Assyrian Empire, in 612 BC after a siege of about three months. An Assyrian remnant under Ashur-uballit II holds out at Harran until 609 BC, and Babylon inherits most of Assyria's former empire.\n",
      "citation": "Via Wikipedia \"Fall of Nineveh\" and \"Medo-Babylonian conquest of the Assyrian Empire\" (searched 2026-09-24): Nineveh falls to the Median-Babylonian coalition in 612 BC after a three-month siege; Ashur-uballit II driven from Harran by 609 BC. Primary source (Babylonian Chronicle ABC 3) not independently read.\n"
    },
    {
      "id": "bantu-expansion",
      "label": "Bantu expansion across sub-Saharan Africa",
      "kind": "period",
      "tMin": 1525.0,
      "tMax": 4025.0,
      "tags": [
        "human-origins",
        "society"
      ],
      "importance": 0.5,
      "description": "Bantu-speaking farmers and iron-workers originate in the Cameroon-Nigeria borderlands and expand across most of sub-Saharan Africa over the following two millennia, a demic migration that genomic evidence dates to roughly 4,000 years ago. Eastern and southern branches of the expansion reach as far as modern KwaZulu-Natal, South Africa, by around AD 300, in the process absorbing or displacing many existing hunter-gatherer populations, ancestral to today's Khoisan and Central African forest peoples.\n",
      "citation": "Fortes-Lima, C.A. et al. (2023). \"The genetic legacy of the expansion of Bantu-speaking peoples in Africa.\" Nature, 625, 540-547. doi:10.1038/s41586-023-06770-6 (demic expansion begins roughly 4,000 years ago in the Cameroon-Nigeria borderlands). Wikipedia, \"Bantu expansion\" (accessed 2026-09-17): eastern/southern branches reach modern KwaZulu-Natal, South Africa, by around AD 300, citing Ehret (1998), Newman (1995) and Shillington (2005); those secondary works not independently read this session.\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "migration",
        "origin": {
          "lat": 6.0,
          "lon": 10.5
        },
        "destination": {
          "lat": -29.0,
          "lon": 31.0
        },
        "established": 1725.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 4025.0
          }
        ]
      }
    },
    {
      "id": "lapita-oceania-expansion",
      "label": "Lapita expansion into Remote Oceania",
      "kind": "period",
      "tMin": 2800.0,
      "tMax": 3325.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.45,
      "description": "Lapita seafarers, makers of the distinctive dentate-stamped pottery that names the culture, expand out of the Bismarck Archipelago (already-settled Near Oceania) into Remote Oceania: pottery appears at Mussau by around 3250 calibrated years BP, then in Vanuatu and Fiji within a couple of centuries, reaching Samoa by roughly 2700 calibrated years BP. This was not the first human presence anywhere in Remote Oceania -- the Mariana Islands were settled independently, and earlier, from the Philippines, around 3500 BP -- but it is the wave that first reached most of Near and Remote Oceania from the Solomons east to Samoa and Tonga.\n",
      "citation": "Denham, T., Bronk Ramsey, C. & Specht, J. (2012). \"Dating the appearance of Lapita pottery in the Bismarck Archipelago and its dispersal to Remote Oceania.\" Archaeology in Oceania, 47(1), 39-46. doi:10.1002/j.1834-4453.2012.tb00113.x (Mussau emergence 3470-3250 cal BP; Vanuatu by 3250-3100 cal BP; Fiji by 3130-3010 cal BP). Petchey, F. & Kirch, P.V. (2019). \"The importance of shell: Redating of the To'aga site (Ofu Island, Manu'a) and a revised chronology for the Lapita to Polynesian Plainware transition in Tonga and Samoa.\" PLOS ONE, 14(9), e0211990. doi:10.1371/journal.pone.0211990 (Samoa, 2785-2607 cal BP). Sefton, J.P. et al. (2022). \"Implications of anomalous relative sea-level rise for the peopling of Remote Oceania.\" PNAS, 119(52), e2210863119. doi:10.1073/pnas.2210863119.\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": -4.0,
          "lon": 148.0
        },
        "destination": {
          "lat": -18.0,
          "lon": 178.0
        },
        "established": 3175.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 3325.0
          }
        ]
      }
    },
    {
      "id": "phoenician-alphabet",
      "label": "Phoenician alphabet emerges",
      "kind": "moment",
      "tMin": 3025.0,
      "tMax": 3125.0,
      "t": 3075.0,
      "tags": [
        "science-technology",
        "society"
      ],
      "importance": 0.5,
      "description": "The Phoenician script — a 22-letter consonantal alphabet ancestral to Greek, Latin, and most alphabets in use today — is conventionally dated to 1050 BC, though this is an acknowledged gap-bridging convention: no Phoenician inscriptions survive securely dated to the 11th century BC itself. The oldest securely dated, fully developed inscriptions come from the 10th century BC (the Ahiram sarcophagus, KAI 1); the al-Khader arrowheads (c. 1100 BC) provide transitional evidence bridging it to the earlier Proto-Canaanite script.\n",
      "citation": "Via Wikipedia \"Phoenician alphabet\": conventional emergence 1050 BC; Ahiram sarcophagus (KAI 1) ~1000 BC; al-Khader arrowheads ~1100 BC. Primary epigraphic sources not independently checked.\n"
    },
    {
      "id": "late-bronze-age-collapse",
      "label": "Late Bronze Age collapse",
      "kind": "period",
      "tMin": 3175.0,
      "tMax": 3225.0,
      "tags": [
        "society",
        "catastrophe"
      ],
      "importance": 0.55,
      "description": "The interlinked palace states of the eastern Mediterranean fall within a few decades: the Hittite empire disintegrates, Mycenaean palaces burn, and Ugarit is destroyed around 1190-1185 BC. Ramesses III's Medinet Habu inscription records repelling the \"Sea Peoples\" in his year 8 (about 1177 BC). The causes, among them drought, earthquakes, invasion and the breakdown of trade, are contested.\n",
      "citation": "Knapp, A.B. & Manning, S.W. (2016). \"Crisis in Context: The End of the Late Bronze Age in the Eastern Mediterranean.\" American Journal of Archaeology, 120(1), 99-149. Kaniewski, D. et al. (2011). \"The Sea Peoples, from Cuneiform Tablets to Carbon Dating.\" PLoS ONE, 6(6), e20232 (northern Levant destruction 1192-1190 BC). Cline, E.H. (2014). 1177 B.C.: The Year Civilization Collapsed. Princeton University Press. Kaniewski, D. et al. (2013). \"Environmental Roots of the Late Bronze Age Crisis.\" PLoS ONE, 8(8), e71004 (drought).\n"
    },
    {
      "id": "4-2-kiloyear-event",
      "label": "4.2 ka aridification event",
      "kind": "period",
      "tMin": 3925.0,
      "tMax": 4275.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.45,
      "description": "A centuries-long drought weakens the Indian monsoon and dries the Mediterranean and west Asia; its onset in a Meghalayan cave stalagmite defines the base of the Meghalayan Age, the latest division of the Holocene. How global it was is contested: a 2024 synthesis of over 1,000 records finds it unremarkable against other Holocene climate swings.\n",
      "citation": "Walker, M. et al. (2018). \"Formal ratification of the subdivision of the Holocene Series/Epoch (Quaternary System/Period): two new GSSPs and three new stages/subseries.\" Episodes, 41(4), 213-223 (Meghalayan GSSP, Mawmluh Cave, 4250 yr b2k = t 4275). Weiss, H. (2016). \"Global megadrought, societal collapse and resilience at 4.2-3.9 ka BP across the Mediterranean and west Asia.\" PAGES Magazine, 24(2), 62-63 (2200-1900 BC). Contested by: McKay, N.P. et al. (2024). \"The 4.2 ka event is not remarkable in the context of Holocene climate variability.\" Nature Communications, 15, 6555.\n"
    },
    {
      "id": "indus-valley-urbanism",
      "label": "Indus Valley Civilisation's Mature Harappan phase",
      "kind": "period",
      "tMin": 3925.0,
      "tMax": 4625.0,
      "tags": [
        "society"
      ],
      "importance": 0.5,
      "description": "The Indus Valley Civilisation's Mature (\"Integration Era\") Harappan phase, roughly 2600-1900 BC, sees Mohenjo-daro and Harappa grow into planned cities of tens of thousands of people each, laid out on street grids with covered brick drains, public wells and standardised fired-brick construction — a scale and uniformity of urban planning with no known contemporary parallel, achieved without the monumental palaces or temples that mark contemporary Egypt and Mesopotamia.\n",
      "citation": "Via Wikipedia \"Indus Valley Civilisation\" and \"Mohenjo-daro\" (accessed 2026-09-17): Mature/Integration Era Harappan phase conventionally 2600-1900 BC; Mohenjo-daro and Harappa populations of 30,000-60,000; covered street drains and over 700 wells at Mohenjo-daro. Primary excavation reports not independently read.\n"
    },
    {
      "id": "austronesian-expansion-taiwan",
      "label": "Austronesian expansion out of Taiwan",
      "kind": "period",
      "tMin": 3525.0,
      "tMax": 5025.0,
      "tags": [
        "human-origins",
        "society"
      ],
      "importance": 0.45,
      "description": "Austronesian-speaking seafarers begin expanding out of Taiwan by around 3000 BC, reaching the previously uninhabited Batanes Islands of the northernmost Philippines — the first known human presence there — by about 2000 BC, per the primary excavation record (no preceramic occupation found across fifty-one radiocarbon-dated samples from seven sites) — the first leg of a maritime dispersal that eventually stretches from Madagascar (madagascar-arrival) to East Polynesia (east-polynesia-arrival) and Aotearoa (aotearoa-arrival). Linguistic and Bayesian phylogenetic evidence corroborates the archaeological picture of a series of expansion pulses moving outward from a Taiwanese homeland.\n",
      "citation": "Bellwood, P. & Dizon, E. (eds.) (2013). 4000 Years of Migration and Cultural Exchange: The Archaeology of the Batanes Islands, Northern Philippines. Terra Australis 40. Canberra: ANU Press. doi:10.22459/TA40.12.2013 (ch.5: no preceramic occupation found at any of seven excavated sites; Batanes prehistory commenced by 2000 BC). Gray, R.D., Drummond, A.J. & Greenhill, S.J. (2009). \"Language Phylogenies Reveal Expansion Pulses and Pauses in Pacific Settlement.\" Science, 323(5913), 479-483. doi:10.1126/science.1166858.\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": 22.0,
          "lon": 120.85
        },
        "destination": {
          "lat": 20.5,
          "lon": 122.0
        },
        "established": 4025.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 5025.0
          }
        ]
      }
    },
    {
      "id": "great-pyramid-giza",
      "label": "Great Pyramid of Giza built",
      "kind": "moment",
      "tMin": 4602.0,
      "tMax": 4638.0,
      "t": 4620.0,
      "tags": [
        "society",
        "science-technology"
      ],
      "importance": 0.35,
      "description": "The Great Pyramid of Giza, Khufu's tomb and the sole surviving Wonder of the Ancient World, is built over roughly a 26-year span; a 2010 Bayesian re-analysis of Egyptian radiocarbon chronology brackets construction to 2613-2577 BC. Earlier mortar-sample radiocarbon dating gave a conflicting, older range (calibrated up to 2871 BC, later reanalysed to 2620-2484 BC using only the youngest samples), and a 2020-dated cedar plank from the Queen's Chamber shaft came back over 500 years too old — both treated as unresolved anomalies here, not used to set the interval.\n",
      "citation": "Ramsey, C.B. et al. (2010), Egyptian radiocarbon chronology re-analysis, 2613-2577 BC. Via Wikipedia \"Great Pyramid of Giza\"; primary paper not independently read.\n"
    },
    {
      "id": "yamnaya-steppe-migration",
      "label": "Yamnaya steppe migration into Europe",
      "kind": "period",
      "tMin": 4325.0,
      "tMax": 5025.0,
      "tags": [
        "human-origins",
        "society"
      ],
      "importance": 0.55,
      "description": "Pastoralist Yamnaya populations from the Pontic-Caspian steppe expand westward into Europe from around 3000 BC, contributing up to three-quarters of the ancestry of the subsequent Corded Ware culture across Central and Northern Europe by around 2500 BC. Ancient-DNA studies link this migration to the spread of Indo-European languages and a marked, sex-biased genetic turnover among the resident Neolithic farmer populations.\n",
      "citation": "Haak, W. et al. (2015). \"Massive migration from the steppe was a source for Indo-European languages in Europe.\" Nature, 522, 207-211. doi:10.1038/nature14317. Allentoft, M.E. et al. (2015). \"Population genomics of Bronze Age Eurasia.\" Nature, 522, 167-172. doi:10.1038/nature14507 (up to ~75% Yamnaya-derived ancestry in the subsequent Corded Ware culture).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "migration",
        "origin": {
          "lat": 48.0,
          "lon": 45.0
        },
        "destination": {
          "lat": 52.0,
          "lon": 12.0
        },
        "established": 4525.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 5025.0
          }
        ]
      }
    },
    {
      "id": "writing",
      "label": "Writing invented",
      "kind": "period",
      "tMin": 5025.0,
      "tMax": 5425.0,
      "tags": [
        "society",
        "science-technology"
      ],
      "importance": 0.75,
      "description": "Proto-cuneiform, the earliest writing system, develops at Uruk in southern Mesopotamia as an administrative technology for tracking goods, labour and rations, before evolving into full logographic cuneiform script by ~3200 BC.\n",
      "citation": "Englund, R.K. (1998). \"Texts from the Late Uruk Period.\" In Mesopotamien: Spaturuk-Zeit und Fruhdynastische Zeit (Orbis Biblicus et Orientalis 160/1). Proto-cuneiform administrative tablets from Uruk date to the Uruk IV-III periods, ~3400-3000 BC.\n"
    },
    {
      "id": "wheel-invented",
      "label": "The wheel is invented",
      "kind": "moment",
      "tMin": 5375.0,
      "tMax": 5656.0,
      "t": 5525.0,
      "tags": [
        "science-technology",
        "society"
      ],
      "importance": 0.55,
      "description": "The earliest evidence for the wheel clusters in the mid-4th millennium BC: wheeled-cart pictographs on clay tablets from Uruk (c. 3500-3350 BC), a wheeled- vehicle image on the Bronocice pot from southern Poland (3631-3380 BC), and wheel tracks and the oldest surviving physical wheel-and-axle, from the Ljubljana Marshes, Slovenia. Independent, near-simultaneous appearances across Mesopotamia and central Europe leave the point of origin — and whether it was invented once or several times — unresolved.\n",
      "citation": "Via Wikipedia \"Wheel\": Uruk (Eanna) pictographs c. 3500-3350 BC; Bronocice pot 3631-3380 BC; Ljubljana Marshes wheel 3340-3030 BC, axle radiocarbon-dated 3360-3045 BC. Underlying excavation reports not independently fetched.\n"
    },
    {
      "id": "uruk-first-city",
      "label": "Uruk becomes the first city",
      "kind": "period",
      "tMin": 5125.0,
      "tMax": 6025.0,
      "tags": [
        "society"
      ],
      "importance": 0.65,
      "description": "Over the Uruk period, small agricultural villages in southern Mesopotamia grow into Uruk, a walled city reaching up to 250 ha with a population of around 50,000 (plus 80,000-90,000 more in its immediate hinterland) by its zenith around 3100 BC — commonly credited as the world's first true city, and the largest urban settlement on Earth at the time.\n",
      "citation": "Nissen, H.J. (2003), population estimates; Harmansah, Ö. (2007), chronology. Via Wikipedia \"Uruk\" (Uruk period conventionally c. 4000-3200 BC, peak extent/population c. 3100 BC); primary works not read directly.\n"
    },
    {
      "id": "neolithic-farmers-europe",
      "label": "Neolithic farmers spread from Anatolia into Europe",
      "kind": "period",
      "tMin": 6925.0,
      "tMax": 8525.0,
      "tags": [
        "human-origins",
        "society"
      ],
      "importance": 0.5,
      "description": "Farming spreads from the Fertile Crescent through Anatolia into Europe as a population movement, not merely a diffusion of ideas: ancient DNA shows migrating farmers, genetically distinct from Europe's resident hunter-gatherers, crossing into the Aegean and Balkans by around 6500 BC and reaching Central Europe's Linear Pottery (LBK) culture by around 5500 BC. The farmers substantially replace, while also admixing with, the Mesolithic populations they encounter, carrying agriculture as far as Britain and Scandinavia over the following two millennia.\n",
      "citation": "Pinhasi, R., Fort, J. & Ammerman, A.J. (2005). \"Tracing the Origin and Spread of Agriculture in Europe.\" PLoS Biology, 3(12), e410. doi:10.1371/journal.pbio.0030410 (radiocarbon wave-of-advance model; farming reaches the Aegean by c. 6500 BC). Haak, W. et al. (2010). \"Ancient DNA from European Early Neolithic Farmers Reveals Their Near Eastern Affinities.\" PLoS Biology, 8(11), e1000536. doi:10.1371/journal.pbio.1000536 (Near Eastern-derived ancestry in Linear Pottery culture farmers, central Germany, c. 5,500 BC). Mathieson, I. et al. (2018). \"The genomic history of southeastern Europe.\" Nature, 555, 197-203. doi:10.1038/nature25778 (Anatolian-related ancestry spreading into the Aegean/Balkans, with substantial genetic replacement of local hunter-gatherers).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "migration",
        "origin": {
          "lat": 38.5,
          "lon": 35.0
        },
        "destination": {
          "lat": 48.5,
          "lon": 16.0
        },
        "established": 7525.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 8525.0
          }
        ]
      }
    },
    {
      "id": "african-humid-period",
      "label": "African Humid Period (Green Sahara)",
      "kind": "period",
      "tMin": 5000.0,
      "tMax": 14600.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.5,
      "description": "Orbitally driven strengthening of the African monsoon turns the Sahara into grassland, lakes and rivers, supporting hippos, crocodiles and human settlement across what is now the world's largest hot desert, before the monsoon weakens and the desert returns. The humid period begins around 14,600-14,500 years ago and ends in stages between roughly 6,000 and 5,000 years ago; some researchers subdivide it into a wetter early phase (AHP I, to ~8,000 years ago) and a drier later phase (AHP II).\n",
      "citation": "deMenocal, P. et al. (2000). \"Abrupt onset and termination of the African Humid Period: rapid climate responses to gradual insolation forcing.\" Quaternary Science Reviews, 19(1-5), 347-361. Liu, Z. et al. (2017). Journal of Geophysical Research: Atmospheres (AHP I/AHP II subdivision at ~8 ka; full paper title UNVERIFIED). Corroborated live via Wikipedia, \"African humid period\" (2026-09-14), which names both papers directly for the same figures.\n"
    },
    {
      "id": "agriculture",
      "label": "Agriculture begins",
      "kind": "period",
      "tMin": 10025.0,
      "tMax": 11525.0,
      "tags": [
        "society"
      ],
      "importance": 0.85,
      "description": "Plant domestication begins in the Fertile Crescent — the first of several independent origins of agriculture worldwide. The transition from cultivation of wild stands to fixed morphological domestication (non-shattering cereals) was gradual, spanning roughly two millennia, so the interval reflects that process rather than a single event.\n",
      "citation": "Zeder, M.A. (2011). \"The Origins of Agriculture in the Near East.\" Current Anthropology, 52(S4), S221-S235. Domestication of founder crops (einkorn, emmer, barley) begins ~10,500-9,500 cal BC, with morphological domestication clearly established by ~8,000 cal BC.\n"
    },
    {
      "id": "gobekli-tepe",
      "label": "Göbekli Tepe monumental site",
      "kind": "period",
      "tMin": 10025.0,
      "tMax": 11525.0,
      "tags": [
        "society",
        "science-technology"
      ],
      "importance": 0.4,
      "description": "Pre-Pottery Neolithic foragers without agriculture, pottery or metal tools raise massive T-shaped limestone pillars into ring enclosures at Göbekli Tepe, southeastern Anatolia — among the earliest monumental architecture anywhere — before the site falls out of use roughly 1,500 years later. The long-standard idea that the enclosures were deliberately backfilled has fallen out of favour since excavator Klaus Schmidt's death; burial is now attributed to natural landslides, with a severe one likely triggering the final abandonment.\n",
      "citation": "Dietrich, O. et al. (2013), radiocarbon dating Layer III to c. 9500 BC; Kinzel, M. & Clare, L. (2020), continued use to c. 8000 BC. Via Wikipedia \"Göbekli Tepe\"; primary radiocarbon papers not read directly.\n"
    },
    {
      "id": "livestock-domestication",
      "label": "Sheep and goat domestication",
      "kind": "period",
      "tMin": 9500.0,
      "tMax": 13025.0,
      "tags": [
        "society",
        "life"
      ],
      "importance": 0.45,
      "description": "Sheep and goats become the first domesticated livestock in the Fertile Crescent, herded alongside the earliest cultivated cereals — a pastoral counterpart to `agriculture`'s plant domestication. Goat domestication is dated genetically to ~9,900-9,500 BP in the Zagros/southeastern Anatolia region; sheep domestication, in the same broader Mesopotamian window (~11,000-8,000 BCE, roughly 13,025-10,025 BP), is less precisely dated — two related but separately documented processes, not one event, hence the wide combined interval.\n",
      "citation": "Naderi, S. et al. (2008). \"The goat domestication process inferred from large- scale mitochondrial DNA analysis of wild and domestic individuals.\" PNAS, 105(46), 17659-17664. Ensminger, M.E. & Parker, R.O. (1986). Sheep and Goat Science, 5th ed. Interstate Printers & Publishers (sheep date range, via Wikipedia \"Domestication of the sheep\").\n"
    },
    {
      "id": "younger-dryas",
      "label": "Younger Dryas cold reversal",
      "kind": "period",
      "tMin": 11700.0,
      "tMax": 12900.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.5,
      "description": "A sharp, roughly 1,300-year return to near-glacial cold interrupts the warming at the end of the last ice age, onsetting in under a century and ending abruptly within decades — one of the fastest, largest climate swings of the whole glacial termination.\n",
      "citation": "Younger Dryas dated to approximately 12,900-11,700 years ago per Britannica, \"Younger Dryas | Definition, Causes, & Termination.\" Rasmussen, S.O. et al. (2006), GICC05 Greenland ice-core chronology (volume and pages UNVERIFIED).\n"
    },
    {
      "id": "natufian-settlements",
      "label": "First permanent settlements (Natufian)",
      "kind": "period",
      "tMin": 11500.0,
      "tMax": 15000.0,
      "tags": [
        "society"
      ],
      "importance": 0.55,
      "description": "Natufian communities across the Levant (Ain Mallaha, El Wad and others) live in sedentary or semi-sedentary villages with stone architecture and food-storage facilities, sustained by wild-food abundance rather than farming — the earliest known durable settlements anywhere, and likely ancestral to the region's first Neolithic villages. They precede plant domestication (`agriculture`) by roughly two millennia, laying the social groundwork — fixed residence, stored surplus — that domestication would later intensify.\n",
      "citation": "Munro, N.D. (2003). \"Small game, the Younger Dryas, and the transition to agriculture in the southern Levant.\" Mitteilungen der Gesellschaft für Urgeschichte, 12, 47-71. Via Wikipedia \"Natufian culture\" (15,000-11,500 BP); primary source not read directly.\n"
    },
    {
      "id": "pleistocene-land-bridges",
      "label": "Beringia, Sunda and Doggerland exposed",
      "kind": "period",
      "tMin": 7000.0,
      "tMax": 30000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.55,
      "description": "Glacial-age sea level, over 100 metres below today's, exposes wide continental shelves as dry land: Beringia connects Siberia to Alaska, the Sunda Shelf joins Sumatra, Java and Borneo to mainland Southeast Asia, and Doggerland links Britain to continental Europe — all drowned again as the ice sheets melt. Each bridge has its own history and does not submerge at the same time (Beringia's main land- bridge phase runs ~30,000-11,000 BP after intermittent earlier connection; Sunda is exposed from the Last Glacial Maximum until a rapid meltwater flood around 14,300 BP; Doggerland's last remnants submerge by roughly 7,000 BP); the interval given is the window over which all three stood substantially above water together, not any one bridge's full individual span.\n",
      "citation": "Elias, S.A. & Brigham-Grette, J. (2007). \"Beringia.\" In Encyclopedia of Quaternary Science. Sathiamurthy, E. & Voris, H.K. (2006). \"Pleistocene Sea Level and Coastline Reconstructions of Sundaland.\" Natural History Journal of Chulalongkorn University, 2, 1-43. Gaffney, V., Fitch, S. & Smith, D. (2009). Europe's Lost World: The Rediscovery of Doggerland. Council for British Archaeology. Per-bridge windows corroborated live via Wikipedia, \"Beringia,\" \"Sunda Shelf\" and \"Doggerland\" (all 2026-09-14).\n"
    },
    {
      "id": "peopling-of-americas",
      "label": "Peopling of the Americas",
      "kind": "period",
      "tMin": 14000.0,
      "tMax": 23255.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.5,
      "description": "Humans reach and spread across the Americas, the last continents to be peopled. Fossilised footprints at White Sands, New Mexico, dated across two stratigraphic layers to 22,860 +/- 320 and 21,130 +/- 250 calibrated years BP, push the earliest secure evidence back to the Last Glacial Maximum, still debated but independently supported by two follow-up dating studies; that is well before the older \"Clovis-first\" model, which placed first peopling at only around 13,000 BP. The pre-Clovis consensus that superseded it -- sites such as Cooper's Ferry, Idaho, dated to ~16,000 years ago -- already placed broad dispersal by roughly 14,000- 16,000 BP; still-older claimed sites (Chiquihuite Cave, the Cerutti Mastodon site) remain without scientific consensus, which is what the interval's older bound reflects, not settled measurement error.\n",
      "citation": "Bennett, M.R. et al. (2021). \"Evidence of humans in North America during the Last Glacial Maximum.\" Science, 373(6562), 1528-1531 (White Sands footprints, 22,860 +/- 320 and 21,130 +/- 250 cal yr BP). Pigati, J.S. et al. (2023). \"Independent age estimates resolve the controversy of ancient human footprints at White Sands.\" Science, 382(6666), 73-75. doi:10.1126/science.adh5007. Holliday, V.T. et al. (2025). \"Paleolake geochronology supports Last Glacial Maximum (LGM) age for human tracks at White Sands, New Mexico.\" Science Advances. doi:10.1126/sciadv.adv4951 (both corroborate, debate continues). Nielsen, R. et al. (2017). \"Tracing the peopling of the world through genomics.\" Nature, 541, 302-310. doi:10.1038/nature21347. Davis, L.G. et al. (2019). \"Late Upper Paleolithic occupation at Cooper's Ferry, Idaho, USA, ~16,000 years ago.\" Science, 365(6456), 891-897. doi:10.1126/science.aax9830.\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": 65.0,
          "lon": -170.0
        },
        "destination": {
          "lat": -10.0,
          "lon": -65.0
        },
        "established": 15000.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 23255.0
          }
        ]
      }
    },
    {
      "id": "last-glacial-maximum",
      "label": "Last Glacial Maximum",
      "kind": "period",
      "tMin": 19000.0,
      "tMax": 26500.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.7,
      "description": "The height of the last ice age: most of the great Northern Hemisphere ice sheets stand at their maximum extent, global sea level sits well over 100 m lower than today, and cold, dry mammoth steppe spreads across northern Eurasia. The interval is the span over which the ice sheets held near-maximum extent, not uncertainty about a single date. Ages are calibrated years before 1950; the 75-year offset from this file's 2025 reference year is far inside the interval.\n",
      "citation": "Clark, P.U. et al. (2009). \"The Last Glacial Maximum.\" Science, 325(5941), 710-714. Most ice sheets reached their maximum extent between 26.5 and 19-20 ka, with deglaciation beginning ~19-20 ka.\n"
    },
    {
      "id": "beringia-arrival",
      "label": "Arrival in Beringia",
      "kind": "moment",
      "tMin": 20000.0,
      "tMax": 32000.0,
      "t": 25000.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.5,
      "description": "Ancient-genome analysis of the Upward Sun River infant (USR1), Alaska, dates population splits and the \"Beringian standstill\" rather than arrival directly: the Ancient Beringian lineage diverges from the ancestral Native American lineage about 20,000 years ago, within a 20,000-25,000-year window for the formation of that ancestral lineage itself. Direct archaeological evidence for people in the region brackets this: the Yana Rhinoceros Horn Site, Siberia, dates human presence at the Arctic edge of Beringia to about 32,000 years ago, while Bluefish Caves, Yukon -- on the Beringian side of the later ice-free corridor -- has a contested radiocarbon case for human presence by about 24,000 years ago. The date used here, 25 ka, is a judgement call within this bracket, not a single securely dated arrival.\n",
      "citation": "Moreno-Mayar, J.V. et al. (2018). \"Terminal Pleistocene Alaskan genome reveals first founding population of Native Americans.\" Nature, 553, 203-207. doi:10.1038/nature25173. Pitulko, V.V. et al. (2004). \"The Yana RHS Site: Humans in the Arctic Before the Last Glacial Maximum.\" Science, 303(5654), 52-56. doi:10.1126/science.1085219. Bourgeon, L., Burke, A. & Higham, T. (2017). \"Earliest Human Presence in North America Dated to the Last Glacial Maximum: New Radiocarbon Dates from Bluefish Caves, Canada.\" PLOS ONE, 12(1), e0169486. doi:10.1371/journal.pone.0169486 (contested).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": 60.0,
          "lon": 125.0
        },
        "destination": {
          "lat": 65.0,
          "lon": -170.0
        },
        "established": 25000.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 32000.0
          }
        ]
      }
    },
    {
      "id": "dog-domestication",
      "label": "Dog domestication",
      "kind": "moment",
      "tMin": 17096.0,
      "tMax": 40000.0,
      "t": 27000.0,
      "tags": [
        "society",
        "life"
      ],
      "importance": 0.35,
      "description": "Dogs diverge from grey wolves through close co-evolution with Late Pleistocene humans, becoming the first domesticated species. Genetic divergence estimates disagree sharply: mitochondrial-genome analysis puts the split at 19,000-32,000 years ago, recalibrated against a Pleistocene wolf's mutation rate to 27,000-40,000 years ago, while the oldest undisputed archaeological dog remains (the Erralla dog, Spain) date to only ~17,100 years ago, already showing selection-altered morphology. The geographic origin of domestication (Siberia, Central Asia, Europe or East Asia) remains unresolved.\n",
      "citation": "Thalmann, O. et al. (2013). \"Complete mitochondrial genomes of ancient canids suggest a European origin of domestic dogs.\" Science, 342(6160), 871-874. Skoglund, P. et al. (2015) / Fan, Z. et al. (2016), Pleistocene-wolf-calibrated divergence of 27,000-40,000 YBP; Erralla dog dated 17,410-17,096 BP. Via Wikipedia \"Domestication of the dog\"; primary genomic papers not read directly.\n"
    },
    {
      "id": "late-quaternary-megafauna-extinction",
      "label": "Late Quaternary megafauna extinctions",
      "kind": "period",
      "tMin": 10000.0,
      "tMax": 50000.0,
      "tags": [
        "life",
        "catastrophe"
      ],
      "importance": 0.6,
      "description": "Most large mammals vanish from every continent except Africa, including mammoths, giant ground sloths and Australia's Diprotodon, at different times on different landmasses. The cause is contested: human hunting and habitat change, climate change, or both in combination.\n",
      "citation": "Koch, P.L. & Barnosky, A.D. (2006). \"Late Quaternary Extinctions: State of the Debate.\" Annual Review of Ecology, Evolution, and Systematics, 37, 215-250 (\"between fifty and ten thousand years ago\"). Barnosky, A.D., Koch, P.L., Feranec, R.S., Wing, S.L. & Shabel, A.B. (2004). \"Assessing the causes of late Pleistocene extinctions on the continents.\" Science, 306, 70-75.\n"
    },
    {
      "id": "neanderthal-sapiens-overlap",
      "label": "Neanderthals and Homo sapiens overlap in Europe",
      "kind": "period",
      "tMin": 39000.0,
      "tMax": 47000.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.55,
      "description": "Homo sapiens is present in Europe from roughly 45-47 ka, while radiocarbon dating of material from 40 Neanderthal sites across Europe shows Neanderthals disappearing from the continent between about 41 and 39 ka. Rather than a single abrupt replacement, populations vanish at different times in different regions, with the two species overlapping there for an estimated 2,600-5,400 years before Neanderthal extinction. The earliest securely dated Homo sapiens presence in Europe is the Initial Upper Palaeolithic layer at Bacho Kiro Cave, Bulgaria, radiocarbon-dated to 45,820-43,650 cal BP and probably present from as early as 46,940 cal BP. A contested, possibly earlier incursion is claimed at Grotte Mandrin, France (Neronian layer E, ~56,800-51,700 years ago), which would place Homo sapiens in Europe well before Bacho Kiro if the association holds.\n",
      "citation": "Higham, T. et al. (2014). \"The timing and spatiotemporal patterning of Neanderthal disappearance.\" Nature, 512, 306-309. Fewlass, H. et al. (2020). \"A 14C chronology for the Middle to Upper Palaeolithic transition at Bacho Kiro Cave, Bulgaria.\" Nature Ecology & Evolution, 4, 794-801. doi:10.1038/s41559-020-1136-3 (Initial Upper Palaeolithic layer, 45,820-43,650 cal BP, probably from 46,940 cal BP). Slimak, L. et al. (2022). \"Modern human incursion into Neanderthal territories 54,000 years ago at Mandrin, France.\" Science Advances, 8, eabj9496. doi:10.1126/sciadv.abj9496 (contested).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": 35.0,
          "lon": 38.0
        },
        "destination": {
          "lat": 45.0,
          "lon": 20.0
        },
        "established": 46000.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 47000.0
          }
        ]
      }
    },
    {
      "id": "east-asia-arrival",
      "label": "Arrival in East Asia",
      "kind": "moment",
      "tMin": 45000.0,
      "tMax": 50000.0,
      "t": 47500.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.5,
      "description": "Ancient-DNA and multimethod redating (AMS radiocarbon, optically stimulated luminescence) of purported early modern-human remains in southern China places their actual arrival within the ~50,000-45,000-year window set by molecular data, consistent with Tianyuan man (~42,000-39,000 years ago, near Beijing). This contradicts much older contested claims for the region, including U-Th dating of flowstones at Fuyan Cave (Daoxian) suggesting 120,000-80,000 years, which the redating study found to be substantially younger, some Holocene in age.\n",
      "citation": "Sun, X. et al. (2021). \"Ancient DNA and multimethod dating confirm the late arrival of anatomically modern humans in southern China.\" PNAS, 118(8), e2019158118. doi:10.1073/pnas.2019158118.\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": 15.0,
          "lon": 100.0
        },
        "destination": {
          "lat": 35.0,
          "lon": 110.0
        },
        "established": 47500.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 50000.0
          }
        ]
      }
    },
    {
      "id": "sahul-arrival",
      "label": "Arrival in Sahul (Australia and New Guinea)",
      "kind": "moment",
      "tMin": 47000.0,
      "tMax": 71000.0,
      "t": 50000.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.55,
      "description": "Optically stimulated luminescence dating at Madjedbebe, in Australia's Northern Territory, leads Clarkson et al. (2017) to state that \"human occupation began around 65,000 years ago\" -- a long chronology also supported by a 2025 mitogenomic study proposing settlement \"by ~60 ka via at least two distinct routes.\" A shorter chronology of ~47,000-51,000 years is argued instead by O'Connell et al. (2018), who question Madjedbebe's stratigraphic integrity, and by Williams et al. (2020), who propose termite bioturbation could explain anomalously old dates at the site; genetic evidence that Sahul's earliest populations share a single pulse of Neanderthal admixture datable to roughly 45,000-50,500 years ago is also read as favouring the shorter chronology. Both readings remain live in the literature -- the arc here is shown dashed across the full contested range and solid from the shorter chronology's estimate.\n",
      "citation": "Clarkson, C. et al. (2017). \"Human occupation of northern Australia by 65,000 years ago.\" Nature, 547, 306-310. doi:10.1038/nature22968. O'Connell, J.F. et al. (2018). \"When did Homo sapiens first reach Southeast Asia and Sahul?\" PNAS, 115(34), 8482-8490. doi:10.1073/pnas.1808385115. Williams, M.A.J., Spooner, N.A., McDonnell, K. & O'Connell, J.F. (2020, published online; 2021 in print). \"Identifying disturbance in archaeological sites in tropical northern Australia.\" Geoarchaeology. doi:10.1002/gea.21822. Sumer, A.P. et al. (2025). Nature. doi:10.1038/s41586-024-08420-x (shared Neanderthal-admixture pulse ~45-49 ka). Gandini, F. et al. (2025). \"Genomic evidence supports the 'long chronology' for the peopling of Sahul.\" Science Advances. doi:10.1126/sciadv.ady9493 (summarises the long, ~60-65 ka, vs. short, 47-51 ka, debate).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": -5.0,
          "lon": 110.0
        },
        "destination": {
          "lat": -15.0,
          "lon": 133.0
        },
        "established": 50000.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 71000.0
          }
        ]
      }
    },
    {
      "id": "south-southeast-asia-arrival",
      "label": "Arrival in South and Southeast Asia",
      "kind": "moment",
      "tMin": 50000.0,
      "tMax": 60000.0,
      "t": 55000.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.5,
      "description": "Modern humans following the main Out-of-Africa dispersal (out-of-africa-migration) reach South and mainland Southeast Asia along a coastally oriented route roughly 60-50 thousand years ago, per genetic and archaeological synthesis. An older, contested claim (Tam Pa Ling, Laos, 70 +/- 3 ka) would push a Southeast Asian presence earlier still; it is not treated as the primary arrival date here.\n",
      "citation": "Mellars, P., Gori, K.C., Carr, M., Soares, P.A. & Richards, M.B. (2013). \"Genetic and archaeological perspectives on the initial modern human colonization of southern Asia.\" PNAS, 110(26), 10699-10704. doi:10.1073/pnas.1306043110. Coastally oriented dispersal dated to approximately 60-50 ka. Freidline, S.E. et al. (2023). \"Early presence of Homo sapiens in Southeast Asia by 86-68 kyr at Tam Pa Ling, Northern Laos.\" Nature Communications, 14, 3193. doi:10.1038/s41467-023-38715-y (contested older claim, TPL 6 dated to 70 +/- 3 ka).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": 28.0,
          "lon": 42.0
        },
        "destination": {
          "lat": 15.0,
          "lon": 100.0
        },
        "established": 55000.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 60000.0
          }
        ]
      }
    },
    {
      "id": "out-of-africa-migration",
      "label": "Out-of-Africa migration",
      "kind": "moment",
      "tMin": 50000.0,
      "tMax": 70000.0,
      "t": 60000.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.6,
      "description": "Genomic evidence dates the principal migration of modern humans out of Africa, ancestral to all non-African populations living today, to this window. The exact route (a northern crossing via Egypt and the Sinai, or a southern one via the Bab el-Mandeb strait) is unresolved and not asserted here. Earlier, smaller dispersals (e.g. into the Levant by ~180 ka, levant-early-dispersal) left populations genetically distinct from this later, successful expansion.\n",
      "citation": "Bergstrom, A., Stringer, C., Hajdinjak, M., Scerri, E.M.L. & Skoglund, P. (2021). \"Origins of modern human ancestry.\" Nature, 590, 229-237. doi:10.1038/s41586-021-03244-5 (\"worldwide expansion of modern humans between 40 and 60 thousand years ago\"). Iasi, L.N.M. et al. (2024). \"Neanderthal ancestry through time: Insights from genomes of ancient and present-day humans.\" Science, 386(6727). doi:10.1126/science.adq3010 (the shared Neanderthal-admixture pulse dating this population's spread to ~50,500-43,500 years ago).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": 15.0,
          "lon": 33.0
        },
        "destination": {
          "lat": 28.0,
          "lon": 42.0
        },
        "established": 60000.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 70000.0
          }
        ]
      }
    },
    {
      "id": "earliest-cave-art",
      "label": "Earliest known cave and rock art",
      "kind": "moment",
      "tMin": 64000.0,
      "tMax": 71600.0,
      "t": 67800.0,
      "tags": [
        "human-origins",
        "society"
      ],
      "importance": 0.6,
      "description": "The oldest securely dated cave art is a hand stencil in Liang Metanduno, Muna Island, Sulawesi, at least 67,800 +/- 3,800 years old (a laser-ablation U-series minimum age). Narrative art, human-like figures with a pig, follows at Leang Karampuang, Sulawesi, by 51,200 years ago. Contested: U-Th ages of over 65,000 years for Iberian cave art attributed to Neanderthals have been disputed, with critics arguing for ~47,000 years.\n",
      "citation": "Oktaviana, A.A. et al. (2026). \"Rock art from at least 67,800 years ago in Sulawesi.\" Nature, 650, 652-656. Oktaviana, A.A. et al. (2024). \"Narrative cave art in Indonesia by 51,200 years ago.\" Nature, 631, 814-818. Hoffmann, D.L. et al. (2018). Science, 359, 912-915. Slimak, L. et al. (2018). Science, 361, eaau1371 (comment).\n"
    },
    {
      "id": "toba-eruption",
      "label": "Toba supereruption",
      "kind": "moment",
      "tMin": 73560.0,
      "tMax": 74200.0,
      "t": 73880.0,
      "tags": [
        "catastrophe",
        "earth-climate"
      ],
      "importance": 0.4,
      "description": "The Youngest Toba eruption in Sumatra is the largest known volcanic event of the last 2.5 million years. Its effect on global climate and on contemporary human populations is heavily contested: the original \"volcanic winter\" hypothesis of a decade-long hemispheric cooling has been challenged by more recent regional climate and archaeological evidence showing human populations persisted through the eruption without a severe bottleneck.\n",
      "citation": "Storey, M., Roberts, R.G. & Saidin, M. (2012). \"Astronomically calibrated 40Ar/39Ar age for the Toba supereruption and global synchronization of late Quaternary records.\" PNAS, 109, 18684-18688 (73.88 +/- 0.32 ka, 1 sigma). Contested effects per \"Understanding the overestimated impact of the Toba volcanic super-eruption on global environments and ancient hominins,\" Earth-Science Reviews (2020).\n"
    },
    {
      "id": "eemian-interglacial",
      "label": "Eemian last interglacial",
      "kind": "period",
      "tMin": 115000.0,
      "tMax": 130000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.45,
      "description": "The most recent interglacial before the present one: global temperatures rival or exceed today's, peaking around 128,000-123,000 years ago and briefly averaging up to ~2 degC warmer than the Holocene; ice sheets retreat further than modern extents (part of the West Antarctic Ice Sheet is thought to have melted), and sea level stands roughly 6-9 metres higher, before the planet tips back into the last glacial period.\n",
      "citation": "Shackleton, N.J., Sanchez-Goni, M.F., Pailler, D. & Lancelot, Y. (2003). \"Marine Isotope Substage 5e and the Eemian Interglacial.\" Global and Planetary Change, 36(3), 151-155. van Leeuwen, J.F.N. et al. (2000), U/Th dating a late-Eemian age of 118.2 +/- 6.3 ka. Full range and peak-warmth window corroborated live via Wikipedia, \"Last interglacial\" (2026-09-14, the current article title for the Eemian), which names Shackleton et al. and van Leeuwen et al. directly for the same figures.\n"
    },
    {
      "id": "levant-early-dispersal",
      "label": "Early dispersal into the Levant",
      "kind": "moment",
      "tMin": 177000.0,
      "tMax": 194000.0,
      "t": 185500.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.45,
      "description": "The Misliya-1 maxilla, from Misliya Cave on Mount Carmel, Israel, is among the earliest known Homo sapiens fossils outside Africa, dated by combined U-Th/ESR and thermoluminescence methods. An older, contested claim for Apidima 1, Greece (>210 ka) is not treated as better-dated here. This early excursion predates the main Out-of-Africa migration (out-of-africa-migration) by well over 100,000 years; ancient-genome analysis indicates modern-human populations that left Africa before about 50 ka, including this one, were genetically distinct from -- and did not contribute ancestry to -- the population whose later expansion is ancestral to living non-African humans.\n",
      "citation": "Hershkovitz, I. et al. (2018). \"The earliest modern humans outside Africa.\" Science, 359(6374), 456-459. doi:10.1126/science.aap8369. Misliya-1 dated to 177,000-194,000 years ago (95% CI), combined U-Th/ESR and thermoluminescence dating. Harvati, K. et al. (2019). \"Apidima Cave fossils provide earliest evidence of Homo sapiens in Eurasia.\" Nature, 571, 500-504. doi:10.1038/s41586-019-1376-z (contested >210 ka claim). Sumer, A.P. et al. (2025). \"Earliest modern human genomes constrain timing of Neanderthal admixture.\" Nature. doi:10.1038/s41586-024-08420-x (early non-African lineages genetically distinct from the later out-of-Africa expansion).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": 15.0,
          "lon": 33.0
        },
        "destination": {
          "lat": 32.7,
          "lon": 35.0
        },
        "established": 185500.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 194000.0
          }
        ]
      }
    },
    {
      "id": "homo-sapiens-origin",
      "label": "Homo sapiens appears",
      "kind": "moment",
      "tMin": 281000.0,
      "tMax": 349000.0,
      "t": 315000.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.9,
      "description": "Fossils from Jebel Irhoud, Morocco, combine a modern-looking face with a more archaic braincase shape. They are among the earliest known members of the Homo sapiens lineage, pushing the species' origins back roughly 100,000 years earlier than previously recognised and supporting a pan-African rather than single-region origin.\n",
      "citation": "Hublin, J.-J. et al. (2017). \"New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens.\" Nature, 546, 289-292. Richter, D. et al. (2017). \"The age of the hominin fossils from Jebel Irhoud, Morocco, and the origins of the Middle Stone Age.\" Nature, 546, 293-296. doi:10.1038/nature22335. Combined age estimate: 315 +/- 34 ka. Bergström, A., Stringer, C., Hajdinjak, M., Scerri, E.M.L. & Skoglund, P. (2021). \"Origins of modern human ancestry.\" Nature, 590, 229-237. doi:10.1038/s41586-021-03244-5 (pan-African population structure).\n",
      "effect": {
        "kind": "arrival",
        "arrivalKind": "peopling",
        "origin": {
          "lat": 2.0,
          "lon": 20.0
        },
        "destination": {
          "lat": 2.0,
          "lon": 20.0
        },
        "established": 315000.0,
        "windows": [
          {
            "tMin": 0.0,
            "tMax": 349000.0
          }
        ]
      }
    },
    {
      "id": "control-of-fire",
      "label": "Habitual control of fire",
      "kind": "period",
      "tMin": 400000.0,
      "tMax": 1500000.0,
      "tags": [
        "human-origins",
        "science-technology"
      ],
      "importance": 0.5,
      "description": "Evidence for hominin-controlled fire ranges from isolated early occurrences (~1.0-1.5 Ma) to unambiguous, habitual, everyday use only from around 400 ka onward. Contested: the gap between sporadic and habitual fire use spans over a million years and the transition is not sharply dated.\n",
      "citation": "Berna, F. et al. (2012). \"Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa.\" PNAS, 109(20), E1215-E1220 (~1.0 Ma). Roebroeks, W. & Villa, P. (2011). \"On the earliest evidence for habitual use of fire in Europe.\" PNAS, 108(13), 5209-5214 (habitual use not clearly established before ~300-400 ka).\n"
    },
    {
      "id": "mid-pleistocene-transition",
      "label": "Mid-Pleistocene Transition",
      "kind": "period",
      "tMin": 700000.0,
      "tMax": 1250000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.5,
      "description": "The rhythm of the ice ages changes: small glacial cycles paced by the 41-kyr cycle of Earth's axial tilt give way to larger, slower ~100-kyr cycles with much bigger ice sheets, with no matching change in orbital forcing. The cause, internal to the climate system, is still debated.\n",
      "citation": "Clark, P.U. et al. (2006). \"The middle Pleistocene transition: characteristics, mechanisms, and implications for long-term changes in atmospheric pCO2.\" Quaternary Science Reviews, 25(23-24), 3150-3184 (MPT began 1250 ka, complete by 700 ka).\n"
    },
    {
      "id": "acheulean-technology",
      "label": "Acheulean handaxe technology begins",
      "kind": "moment",
      "tMin": 1720000.0,
      "tMax": 1950000.0,
      "t": 1835000.0,
      "tags": [
        "human-origins",
        "science-technology"
      ],
      "importance": 0.5,
      "description": "Symmetrical, bifacially flaked handaxes appear by about 1.95 Ma at Melka Kunture, Ethiopia, and by 1.76 Ma at Kokiselei, West Turkana, Kenya, a marked advance in complexity over the simple Oldowan flakes that preceded them.\n",
      "citation": "Mussi, M. et al. (2023). \"Early Homo erectus lived at high altitudes and produced both Oldowan and Acheulean tools.\" Science, eadd9115. Lepre, C.J. et al. (2011). \"An earlier origin for the Acheulian.\" Nature, 477, 82-85. Kokiselei 4 dated to 1.76 Ma (nonlinear interpolation) / 1.72 Ma (linear interpolation) via magnetostratigraphy bracketed by dated volcanic ash.\n"
    },
    {
      "id": "homo-erectus",
      "label": "Homo erectus appears",
      "kind": "moment",
      "tMin": 1500000.0,
      "tMax": 2040000.0,
      "t": 2000000.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.7,
      "description": "Homo erectus, the first hominin with fully modern human body proportions, appears in Africa. The oldest confirmed fossil, KNM-ER 2598, is securely dated to older than 1.855 Ma; the species is conventionally held to have evolved roughly 2 million years ago, and its fossils persist across Africa and Asia for well over a million years afterward.\n",
      "citation": "\"New hominin remains and revised context from the earliest Homo erectus locality in East Turkana, Kenya.\" Nature Communications (2021), article s41467-021-22208-x (KNM-ER 2598, >1.855 Ma). Herries, A.I.R. et al. (2020). \"Contemporaneity of Australopithecus, Paranthropus, and early Homo erectus in South Africa.\" Science, 368, eaaw7293 (DNH 134, ~2.04-1.95 Ma). Mussi, M. et al. (2023). Science, eadd9115 (Melka Kunture mandible ca. 2 Ma).\n"
    },
    {
      "id": "quaternary-glaciation-begins",
      "label": "Quaternary Period begins",
      "kind": "moment",
      "tMin": 2580000.0,
      "tMax": 2580000.0,
      "t": 2580000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.6,
      "description": "The base of the Gelasian Stage marks the start of the Quaternary Period and the Pleistocene Series, and the onset of major, sustained Northern Hemisphere glaciation — the beginning of the ice-age cycles the planet has lived through ever since.\n",
      "citation": "GSSP for the base of the Gelasian Stage, Monte San Nicola, Italy, per the ICS International Chronostratigraphic Chart v2024/12: 2.58 Ma.\n"
    },
    {
      "id": "isthmus-of-panama",
      "label": "Isthmus of Panama forms",
      "kind": "moment",
      "tMin": 2800000.0,
      "tMax": 16000000.0,
      "t": 2800000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.55,
      "description": "A continuous land connection rises between North and South America, closing the Central American Seaway and triggering the Great American Biotic Interchange. Contested: one synthesis dates final closure to ~2.8 Ma (O'Dea et al. 2016), biological evidence argues for earlier, stepwise emergence (Bacon et al. 2015), and detrital-zircon evidence suggests the deep seaway had already closed by the middle Miocene (Montes et al. 2015).\n",
      "citation": "O'Dea, A. et al. (2016). \"Formation of the Isthmus of Panama.\" Science Advances, 2(8), e1600883 (~2.8 Ma final closure). Bacon, C.D. et al. (2015). \"Biological evidence supports an early and complex emergence of the Isthmus of Panama.\" PNAS, 112(19), 6110-6115 (contested, early-emergence hypothesis). Montes, C. et al. (2015). \"Middle Miocene closure of the Central American Seaway.\" Science, 348, 226-229.\n"
    },
    {
      "id": "australopithecus-afarensis",
      "label": "Lucy (AL 288-1), Australopithecus afarensis",
      "kind": "moment",
      "tMin": 3180000.0,
      "tMax": 3220000.0,
      "t": 3200000.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.65,
      "description": "The AL 288-1 skeleton (\"Lucy\"), discovered at Hadar, Ethiopia in 1974, is the most complete Australopithecus afarensis specimen known: an ape-sized skull paired with a pelvis and leg bones built for upright bipedal walking.\n",
      "citation": "Discovered by Donald Johanson's team, Hadar, Ethiopia, 24 November 1974. Age and description per the Natural History Museum, \"Australopithecus afarensis, Lucy's species,\" and Britannica, \"Lucy | Australopithecus afarensis, 3.2 Million Years, Ethiopia.\" Smithsonian National Museum of Natural History, Human Origins Program, \"Australopithecus afarensis\" (species range ~3.85-2.95 Ma).\n"
    },
    {
      "id": "lomekwi-stone-tools",
      "label": "Oldest known stone tools (Lomekwi 3)",
      "kind": "moment",
      "tMin": 3250000.0,
      "tMax": 3350000.0,
      "t": 3300000.0,
      "tags": [
        "human-origins",
        "science-technology"
      ],
      "importance": 0.6,
      "description": "Stone artefacts at Lomekwi 3, West Turkana, Kenya, predate the Oldowan industry by roughly 700,000 years and are the oldest known deliberately flaked stone tools — made 500,000 years before the genus Homo appears in the fossil record, contradicting the long-standing assumption that toolmaking began with Homo. Questioned: some researchers remain sceptical that the artefacts are securely of Pliocene age.\n",
      "citation": "Harmand, S. et al. (2015). \"3.3-million-year-old stone tools from Lomekwi 3, West Turkana, Kenya.\" Nature, 521, 310-315. Dominguez-Rodrigo, M. & Alcala, L. (2019). \"Pliocene Archaeology at Lomekwi 3? New Evidence Fuels More Skepticism.\" Journal of African Archaeology, doi:10.1163/21915784-20190006.\n"
    },
    {
      "id": "messinian-salinity-crisis",
      "label": "Messinian salinity crisis",
      "kind": "period",
      "tMin": 5330000.0,
      "tMax": 5960000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.55,
      "description": "Tectonic closure of the Atlantic gateways, the Betic and Rifian corridors through southern Spain and northern Morocco, isolates the Mediterranean from the Atlantic; extreme evaporation deposits kilometre-scale salt beds across the basin floor. The crisis ends at 5.33 Ma when Atlantic water floods back through the Strait of Gibraltar in the Zanclean flood. Contested: how dry the basin actually became, and how catastrophic the final refill was, remain disputed.\n",
      "citation": "Krijgsman, W., Hilgen, F.J., Raffi, I., Sierro, F.J. & Wilson, D.S. (1999). \"Chronology, causes and progression of the Messinian salinity crisis.\" Nature, 400, 652-655 (onset chronology). Garcia-Castellanos, D. et al. (2009). \"Catastrophic flood of the Mediterranean after the Messinian Salinity Crisis.\" Nature, 462, 778-781 (Zanclean reflooding).\n"
    },
    {
      "id": "c4-expansion",
      "label": "C4 grasses expand across the tropics",
      "kind": "period",
      "tMin": 5000000.0,
      "tMax": 8000000.0,
      "tags": [
        "life",
        "earth-climate"
      ],
      "importance": 0.65,
      "description": "Carbon-isotope evidence from fossil soils and tooth enamel across multiple continents records the late Miocene replacement of C3-dominated woodland and grassland by C4-dominated open savanna, a major shift in the base of terrestrial food webs and the habitat in which the human lineage's own later evolution plays out. Timing varied by region, and C3 woodland persisted in places such as Greece (Quade, Solounias & Cerling 1994).\n",
      "citation": "Cerling, T.E., Harris, J.M., MacFadden, B.J., Leakey, M.G., Quade, J., Eisenmann, V. & Ehleringer, J.R. (1997). \"Global vegetation change through the Miocene/Pliocene boundary.\" Nature, 389, 153-158. Cerling, T.E., Ehleringer, J.R. & Harris, J.M. (1998). Phil. Trans. R. Soc. B, 353, 159-170 (C4 biomass in mammal diets in Asia, Africa, North and South America ~8-5 Ma). Uno, K.T. et al. (2011). PNAS, 108, 6509-6514 (East African bovids on C4-dominated diets by 7.4 Ma; equids taking significant C4 by ~9.9-9.6 Ma).\n"
    },
    {
      "id": "hominins",
      "label": "First hominins",
      "kind": "moment",
      "tMin": 6000000.0,
      "tMax": 7200000.0,
      "t": 7000000.0,
      "tags": [
        "human-origins"
      ],
      "importance": 0.8,
      "description": "Sahelanthropus tchadensis, from Chad, is the earliest widely proposed hominin, with skeletal evidence interpreted by its describers as consistent with bipedalism. Contested: its age predates the molecular estimate for the human-chimpanzee split (~6.3-5.4 Ma), and its classification as a hominin rather than a stem great ape is actively debated.\n",
      "citation": "Brunet, M. et al. (2002). \"A new hominid from the Upper Miocene of Chad, Central Africa.\" Nature, 418, 145-151. Site dated 7.2-6.8 Ma via biostratigraphy and cosmogenic nuclide dating (Lebatard, A.-E. et al. 2008, PNAS, 105(9), 3226-3231).\n"
    },
    {
      "id": "hipparion-dispersal",
      "label": "Hipparionine horses reach the Old World",
      "kind": "moment",
      "tMin": 11100000.0,
      "tMax": 11400000.0,
      "t": 11250000.0,
      "tags": [
        "life"
      ],
      "importance": 0.4,
      "description": "Three-toed hipparionine horses disperse from North America across the Bering land bridge into Eurasia and Africa, a rapid, near-synchronous \"Hipparion datum\" long taken as a marker for the westward spread of open savanna — though open C3 grassland habitats are now known to predate their arrival in some regions.\n",
      "citation": "\"Old World first appearance datum of 'Hipparion' horses: Late Miocene large-mammal dispersal and global events.\" Geology, 25(1), 19-22 (1997). First appearance at Chron C5r, minimum age 11.1 Ma; Hippotherium primigenium at Atzelsdorf, Austria, ~11.2-11.4 Ma.\n"
    },
    {
      "id": "middle-miocene-climatic-optimum",
      "label": "Miocene Climatic Optimum",
      "kind": "period",
      "tMin": 14700000.0,
      "tMax": 16900000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.45,
      "description": "A roughly two-million-year warm spell when global temperatures were about 7-8 °C above today's, with CO2 comparable to near-future levels. It ends in the Middle Miocene Climate Transition, when the Antarctic ice sheet expands permanently, with the main step at about 13.9-13.8 Ma.\n",
      "citation": "Steinthorsdottir, M. et al. (2021). \"The Miocene: the future of the past.\" Paleoceanography and Paleoclimatology, 36(4), e2020PA004037 (MCO ~16.9-14.7 Ma, ~7-8 °C warmer). Holbourn, A. et al. (2014). \"Middle Miocene climate cooling linked to intensification of eastern equatorial Pacific upwelling.\" Geology, 42, 19-22 (main MMCT step 13.9-13.8 Ma).\n"
    },
    {
      "id": "grassland-spread",
      "label": "Spread of C3 grasslands",
      "kind": "period",
      "tMin": 15500000.0,
      "tMax": 23000000.0,
      "tags": [
        "life",
        "earth-climate"
      ],
      "importance": 0.55,
      "description": "The first definitive grass-dominated open habitats appear in the early Miocene, though forest and woodland remain globally dominant. Phytolith diversity in open-habitat grasses rises through the late early Miocene and early late Miocene, roughly 19-15.5 Ma, marking the start of the multistage shift from a forested to a grassland-dominated world that later culminates in the Late Neogene spread of C4 grasses.\n",
      "citation": "Stromberg, C.A.E. (2005). \"Decoupled taxonomic radiation and ecological expansion of open-habitat grasses in the Cenozoic of North America.\" PNAS, 102, 11980-11984 (open-habitat grass dominance in North America by the late Oligocene-early Miocene). Stromberg, C.A.E. (2011). \"Evolution of Grasses and Grassland Ecosystems.\" Annual Review of Earth and Planetary Sciences, 39, 517-544.\n"
    },
    {
      "id": "antarctic-circumpolar-current",
      "label": "Drake Passage opens; proto-Antarctic Circumpolar Current",
      "kind": "moment",
      "tMin": 21000000.0,
      "tMax": 34000000.0,
      "t": 27500000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.45,
      "description": "The opening of the Drake Passage lets an eastward current begin to encircle Antarctica, thermally isolating the continent. Contested and poorly constrained: estimates for the onset range from the Eocene-Oligocene boundary (~34 Ma) through 31-26 Ma to 23.5 +/- 2.5 Ma for a proto-current. The modern, deep-reaching current came later: Evangelinos et al. (2024) place its onset in the late Miocene, so this interval marks the gateway opening, not the modern current.\n",
      "citation": "Evangelinos, D. et al. (2024). \"Late Miocene onset of the modern Antarctic Circumpolar Current.\" Nature Geoscience, 17, 165-170. \"Drake Passage gateway opening and Antarctic Circumpolar Current onset 31 Ma ago: The message of foraminifera and reconsideration of the Neodymium isotope record.\" Chemical Geology (2021) (31-26 Ma estimate).\n"
    },
    {
      "id": "paraceratherium",
      "label": "Paraceratherium, a giant hornless rhino",
      "kind": "period",
      "tMin": 23000000.0,
      "tMax": 34000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.4,
      "description": "Hornless giant rhinocerotoids browse the Oligocene woodlands of Asia from Mongolia and Kazakhstan to Pakistan and Gansu. At an estimated 11-20 tonnes and nearly 5 m at the shoulder, Paraceratherium is among the largest land mammals known.\n",
      "citation": "Deng, T. et al. (2021). \"An Oligocene giant rhino provides insights into Paraceratherium evolution.\" Communications Biology, 4, 639 (P. linxiaense, 26.5 Ma, Linxia Basin). Fortelius, M. & Kappelman, J. (1993). \"The largest land mammal ever imagined.\" Zoological Journal of the Linnean Society, 108, 85-101 (mean ~11 t, maximum 15-20 t). Prothero, D.R. (2013). Rhinoceros Giants: The Paleobiology of Indricotheres. Indiana University Press. Genus range treated as the Oligocene (~34-23 Ma); exact first and last appearances UNVERIFIED against primary literature.\n"
    },
    {
      "id": "eocene-oligocene-transition",
      "label": "Eocene-Oligocene transition; first Antarctic ice sheet",
      "kind": "period",
      "tMin": 33650000.0,
      "tMax": 34400000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.75,
      "description": "Earth's climate steps from the early Cenozoic greenhouse into the modern icehouse: the Antarctic ice sheet grows rapidly in two pulses, the EOT-1 cooling event (~34.1-33.9 Ma) and the larger Oi-1 glaciation (~33.8-33.6 Ma), reaching the coastline for the first time. The associated cooling drives a major mammalian faunal turnover in Europe known as the Grande Coupure.\n",
      "citation": "Hutchinson, D.K. et al. (2021). \"The Eocene-Oligocene transition: a review of marine and terrestrial proxy data, models and model-data comparisons.\" Climate of the Past, 17, 269 (EOT 34.44-33.65 Ma). Coxall, H.K. et al. (2005). \"Rapid stepwise onset of Antarctic glaciation and deep-sea acidification in the late Eocene.\" Nature, 433, 53-57. Eocene-Oligocene boundary age 33.9 Ma per the ICS International Chronostratigraphic Chart v2024/12. \"Grande Coupure\" term coined by Stehlin, H.G. (1910).\n"
    },
    {
      "id": "chesapeake-bay-impact-crater",
      "label": "Chesapeake Bay impact",
      "kind": "moment",
      "tMin": 35200000.0,
      "tMax": 35800000.0,
      "t": 35500000.0,
      "tags": [
        "catastrophe",
        "earth-climate"
      ],
      "importance": 0.4,
      "description": "An asteroid strikes the edge of the continental shelf off what is now Virginia, USA, excavating an 85 km crater — one of the best-preserved \"wet-target\" impact structures known, now buried beneath the mouth of Chesapeake Bay. It forms within about 25,000 years of the Popigai impact (above); geochemical evidence for two chemically distinct impactor types rules out a single parent-body breakup, pointing instead to an unexplained multi-source asteroid shower.\n",
      "citation": "Poag, C.W., Koeberl, C. & Reimold, W.U. (2004). The Chesapeake Bay Crater: Geology and Geophysics of a Late Eocene Submarine Impact Structure. Springer. Schmitz, B. et al. (2015). \"Fragments of Late Eocene Earth-impacting asteroids linked to disturbance of asteroid belt.\" Earth and Planetary Science Letters, 425, 77-83.\n"
    },
    {
      "id": "popigai-impact-crater",
      "label": "Popigai impact",
      "kind": "moment",
      "tMin": 35500000.0,
      "tMax": 35900000.0,
      "t": 35700000.0,
      "tags": [
        "catastrophe",
        "earth-climate"
      ],
      "importance": 0.4,
      "description": "An asteroid strikes northern Siberia, excavating a 90-100 km crater and shock-converting graphite in the target rock into microscopic diamonds — the source of one of the world's largest diamond deposits. It forms within about 25,000 years of the Chesapeake Bay impact (below), and a link between the two impacts and the Eocene-Oligocene cooling step that follows soon after has been proposed but is not established: a 2024 reassessment found no paleoclimatic anomaly associated with either impact.\n",
      "citation": "Bottomley, R., Grieve, R., York, D. & Masaitis, V. (1997). \"The age of the Popigai impact event and its relation to events at the Eocene/Oligocene boundary.\" Nature, 388(6640), 365-368. Wade, B. & Cheng, N.K.Y. (2024). \"No paleoclimatic anomalies are associated with the late Eocene extraterrestrial impact events.\" Communications Earth & Environment, 5, 710.\n"
    },
    {
      "id": "whales-return-to-sea",
      "label": "Whales return to the sea",
      "kind": "period",
      "tMin": 41000000.0,
      "tMax": 50000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.55,
      "description": "Whales evolve from land-dwelling artiodactyls: wolf-sized pakicetids of Indo-Pakistan were \"no more amphibious than a tapir\", yet within about ten million years basilosaurids such as Tutcetus in the Tethys Sea off Egypt had cut all ties to land. The start is contested, because the age of the Kuldana Formation that yields Pakicetus is argued as late early Eocene (~50 Ma) or early middle Eocene.\n",
      "citation": "Thewissen, J.G.M., Williams, E.M., Roe, L.J. & Hussain, S.T. (2001). \"Skeletons of terrestrial cetaceans and the relationship of whales to artiodactyls.\" Nature, 413, 277-281. Gingerich, P.D. (2003). \"Stratigraphic and micropaleontological constraints on the middle Eocene age of the mammal-bearing Kuldana Formation of Pakistan.\" Journal of Vertebrate Paleontology, 23(3), 643-651. Antar, M.S. et al. (2023). \"A diminutive new basilosaurid whale reveals the trajectory of the cetacean life histories during the Eocene.\" Communications Biology, 6, 707 (Tutcetus, ~41 Ma, Fayum). Uhen, M.D. (2010). \"The Origin(s) of Whales.\" Annual Review of Earth and Planetary Sciences, 38, 189-219 (first whales ~52.5 Ma).\n"
    },
    {
      "id": "india-asia-collision",
      "label": "India-Asia collision begins",
      "kind": "moment",
      "tMin": 34000000.0,
      "tMax": 59000000.0,
      "t": 46500000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.6,
      "description": "India's continental margin collides with Asia, initiating the Himalayan orogeny and the uplift of the Tibetan Plateau — a collision still ongoing today. Contested: the timing of initial contact is one of the most debated questions in Earth science, with proposals ranging from a middle-Paleocene 59 +/- 1 Ma sediment-provenance signal to paleomagnetic estimates as young as 34 Ma.\n",
      "citation": "Aitchison, J.C., Ali, J.R. & Davis, A.M. (2007). \"When and where did India and Asia collide?\" Journal of Geophysical Research: Solid Earth, 112, B05423 (review of competing timing estimates spanning 70-34 Ma). Middle-Paleocene 59 +/- 1 Ma sediment-provenance estimate per \"The timing of India-Asia collision onset: facts, theories, controversies,\" Earth-Science Reviews (2016).\n"
    },
    {
      "id": "messel-pit",
      "label": "Messel Pit fossil lake",
      "kind": "moment",
      "tMin": 47200000.0,
      "tMax": 48500000.0,
      "t": 47500000.0,
      "tags": [
        "life",
        "earth-climate"
      ],
      "importance": 0.4,
      "description": "A volcanic maar lake near Darmstadt, Germany, set in paratropical rainforest just after the Early Eocene Climatic Optimum, fills with annually laminated oil shale over roughly 640 kyr. Its anoxic bottom preserves whole skeletons with skin, hair, feathers and stomach contents: the early horse Eurohippus, the primate Darwinius, crocodilians such as Diplocynodon, bats, birds and insects.\n",
      "citation": "Lenz, O.K., Wilde, V., Mertz, D.F. & Riegel, W. (2015). \"New palynology-based astronomical and revised 40Ar/39Ar ages for the Eocene maar lake of Messel (Germany).\" International Journal of Earth Sciences, 104, 873-889 (eruption 48.27-48.11 +/- 0.22 Ma depending on Fish Canyon calibration; lake record ~640 kyr), revising Mertz, D.F. & Renne, P.R. (2005), Courier Forschungsinstitut Senckenberg, 255, 67-75 (47.8 +/- 0.2 Ma). Schmitt, C. et al. (2024). \"Eocene maar sediments record warming of up to 3.5 °C during a hyperthermal event 47.2 million years ago.\" Communications Earth & Environment (Middle Messel Formation 47.65-47.22 Ma; volume and article number UNVERIFIED). Franzen, J.L. et al. (2009). PLoS ONE, 4(5), e5723 (Darwinius masillae).\n"
    },
    {
      "id": "early-eocene-climatic-optimum",
      "label": "Early Eocene Climatic Optimum",
      "kind": "period",
      "tMin": 49000000.0,
      "tMax": 54000000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.55,
      "description": "The warmest sustained interval of the last 66 million years. Swamp forests, crocodilians and year-round mammal residents such as Coryphodon live above the Arctic Circle. Published bounds vary, from about 53-50 Ma to about 54-49 Ma.\n",
      "citation": "Woodburne, M.O., Gunnell, G.F. & Stucky, R.K. (2009). PNAS, 106(32), 13399-13403 (EECO 53-50 Ma). Eberle, J.J. et al. (2014). PLOS ONE, 9(5), e96079. Eberle, J.J., Fricke, H.C. & Humphrey, J.D. (2009). \"Lower-latitude mammals as year-round residents in Eocene Arctic forests.\" Geology, 37, 499-502.\n"
    },
    {
      "id": "petm",
      "label": "Paleocene-Eocene Thermal Maximum (PETM)",
      "kind": "period",
      "tMin": 55800000.0,
      "tMax": 56000000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.55,
      "description": "A sudden release of isotopically light carbon drives several degrees of global warming in geologically almost no time, the most extreme of several Cenozoic hyperthermals. The rapid onset (on the order of 6 kyr) is followed by a ~100-170 kyr warm \"body\" phase and a slower ~50-135 kyr recovery.\n",
      "citation": "Kirtland Turner, S. (2018). \"Constraints on the onset duration of the Paleocene-Eocene Thermal Maximum.\" Philosophical Transactions of the Royal Society A, 376(2130), 20170082. Onset dated to 55.9-56.0 Ma.\n"
    },
    {
      "id": "paleocene-mammal-radiation",
      "label": "Paleocene mammal radiation",
      "kind": "period",
      "tMin": 56000000.0,
      "tMax": 66043000.0,
      "tags": [
        "life"
      ],
      "importance": 0.5,
      "description": "In the aftermath of the K-Pg extinction, placental mammals rapidly radiate to fill the large-herbivore niches the non-avian dinosaurs left empty: mammal maximum body size is near pre-extinction values within ~100 kyr and has tripled by ~300 kyr. Pantodonts such as Pantolambda, a heavy-bodied browsing mammal, appear by the mid-Paleocene; the interval spans the radiation from the extinction to the close of the Paleocene.\n",
      "citation": "Lyson, T.R. et al. (2019). \"Exceptional continental record of biotic recovery after the Cretaceous-Paleogene mass extinction.\" Science, 366, 977-983. Halliday, T.J.D., Upchurch, P. & Goswami, A. (2017; online 2015). \"Resolving the relationships of Paleocene placental mammals.\" Biological Reviews, 92(1), 521-550. Pantolambda ~63-57 Ma per Wikipedia, \"Pantolambda\" (tertiary; the weakest source in this record).\n"
    },
    {
      "id": "primates",
      "label": "First primates",
      "kind": "moment",
      "tMin": 56000000.0,
      "tMax": 65900000.0,
      "t": 65900000.0,
      "tags": [
        "life"
      ],
      "importance": 0.7,
      "description": "Purgatorius, a stem primate from Montana, appears within roughly 150,000 years of the K-Pg extinction. Crown-group primates (Euprimates, e.g. Teilhardina) are not securely documented until ~56 Ma — the interval spans this stem-vs-crown ambiguity.\n",
      "citation": "Wilson Mantilla, G.P. et al. (2021). \"Earliest Palaeocene purgatoriids and the initial radiation of stem primates.\" Royal Society Open Science, 8(2), 210050 (Purgatorius, ~65.9 Ma). Smith, T., Rose, K.D. & Gingerich, P.D. (2006) for Teilhardina, oldest crown primate, ~55.8 Ma.\n"
    },
    {
      "id": "deccan-traps",
      "label": "Deccan Traps eruptions",
      "kind": "period",
      "tMin": 65600000.0,
      "tMax": 66300000.0,
      "tags": [
        "catastrophe",
        "earth-climate"
      ],
      "importance": 0.5,
      "description": "Massive flood-basalt volcanism in west-central India straddles the K-Pg boundary, with the bulk of the eruptive volume concentrated in the ~66-65 Ma window. A long-running debate weighs Deccan volcanism against the Chicxulub impact (below) as a contributor to the end-Cretaceous extinction; a 2015 study argued the impact itself triggered a shift in Deccan's eruptive tempo.\n",
      "citation": "Schoene, B. et al. (2021). \"An evaluation of Deccan Traps eruption rates using geochronologic data.\" Geochronology, 3(1), 181-198. Renne, P.R. et al. (2015). \"State shift in Deccan volcanism at the Cretaceous-Paleogene boundary, possibly induced by impact.\" Science, 350(6256), 76-78.\n"
    },
    {
      "id": "k-pg-aftermath",
      "label": "K-Pg aftermath fern spike",
      "kind": "period",
      "tMin": 66038000.0,
      "tMax": 66043000.0,
      "tags": [
        "life",
        "catastrophe"
      ],
      "importance": 0.5,
      "description": "Over roughly the first thousand years at well-dated sites after the Chicxulub impact, sections worldwide (most densely sampled in North America and New Zealand) record a sharp spike in fern spores — a \"fern spike\" — as ferns, opportunistic recolonisers of disturbed ground, dominate a landscape stripped of the forest that stood before impact.\n",
      "citation": "Vajda, V., Raine, J.I. & Hollis, C.J. (2001). \"Indication of global deforestation at the Cretaceous-Tertiary boundary by New Zealand fern spike.\" Science, 294(5547), 1700-1702.\n"
    },
    {
      "id": "k-pg-impact",
      "label": "K-Pg impact",
      "kind": "moment",
      "tMin": 66032000.0,
      "tMax": 66054000.0,
      "t": 66043000.0,
      "tags": [
        "catastrophe",
        "earth-climate"
      ],
      "importance": 1.0,
      "description": "The Chicxulub asteroid impacts the Yucatan Peninsula, triggering the Cretaceous-Paleogene mass extinction that ends the age of non-avian dinosaurs.\n",
      "citation": "Renne, P.R. et al. (2013). \"Time scales of critical events around the Cretaceous-Paleogene boundary.\" Science, 339(6120), 684-687. Chicxulub impact and K-Pg boundary dated to 66.043 +/- 0.011 Ma.\n",
      "effect": {
        "kind": "impact-winter",
        "anchor": {
          "lat": 21.3,
          "lon": -89.5
        },
        "windows": [
          {
            "tMin": 66032000.0,
            "tMax": 66054000.0
          }
        ]
      }
    },
    {
      "id": "mosasaurs",
      "label": "Age of mosasaurs",
      "kind": "period",
      "tMin": 66043000.0,
      "tMax": 98000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.45,
      "description": "Marine lizards related to monitors and snakes appear ~98 Ma and, once ichthyosaurs and pliosaurs are gone, become the top predators of Late Cretaceous seas from the Turonian onward, before dying out in the K-Pg extinction.\n",
      "citation": "Polcyn, M.J., Jacobs, L.L., Araujo, R., Schulp, A.S. & Mateus, O. (2014). \"Physical drivers of mosasaur evolution.\" Palaeogeography, Palaeoclimatology, Palaeoecology, 400, 17-27 (a 32.5 Myr history from their appearance at 98 Ma, Haasiasaurus, to the K-Pg boundary). K-Pg boundary 66.043 Ma per Renne et al. (2013), as for k-pg-impact.\n"
    },
    {
      "id": "western-interior-seaway",
      "label": "Western Interior Seaway",
      "kind": "period",
      "tMin": 66000000.0,
      "tMax": 100000000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.45,
      "description": "A shallow epicontinental sea floods the middle of North America through the Cretaceous greenhouse's high sea level, splitting the continent into the western landmass Laramidia and the eastern Appalachia for roughly 34 million years, before draining at the very end of the Cretaceous. Its final closure lines up with the K-Pg boundary already anchored elsewhere in this file by k-pg-impact.\n",
      "citation": "Roberts, L.N.R. & Kirschbaum, M.A. (1995). \"Paleogeography of the Late Cretaceous of the Western Interior of Middle North America — Coal Distribution and Sediment Accumulation.\" USGS Professional Paper 1561. The 100-66 Ma bracket was corroborated live via Wikipedia, \"Western Interior Seaway\" (2026-09-14); UNVERIFIED — that article's own citations do not name the USGS paper directly, though its stated 100-66 Ma range matches it.\n"
    },
    {
      "id": "angiosperm-radiation",
      "label": "Flowering plants spread and radiate",
      "kind": "period",
      "tMin": 80000000.0,
      "tMax": 125000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.55,
      "description": "Within the \"Cretaceous Terrestrial Revolution,\" angiosperms spread from a marginal lake-edge presence to ecological dominance over roughly 45 million years, coevolving with pollinating insects and reshaping terrestrial food webs; the traditional bound is 125-80 Ma, though some authors extend the revolution's later phase into the Paleogene.\n",
      "citation": "Lloyd, G.T. et al. (2008). \"Dinosaurs and the Cretaceous Terrestrial Revolution.\" Proceedings of the Royal Society B, 275(1650), 2483-2490. Benton, M.J., Wilf, P. & Sauquet, H. \"The Angiosperm Terrestrial Revolution and the origins of modern biodiversity.\" New Phytologist, 233(5), 2017-2035 (UNVERIFIED: year given as 2021; the volume may be dated 2022).\n"
    },
    {
      "id": "earliest-pollinating-insects",
      "label": "Earliest pollinating insects",
      "kind": "period",
      "tMin": 93000000.0,
      "tMax": 165000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.5,
      "description": "Long-proboscid scorpionflies (Aneuretopsychidae and kin, Jurassic-Cretaceous, ~165-93 Ma) carry a tubular mouthpart interpreted as adapted to drink the pollination droplets of insect-pollinated gymnosperms such as Bennettitales, evidence for insect pollination well before flowers existed. Contested: a separate ~100 Ma Burmese-amber specimen, Melittosphex burmensis, was described as the oldest bee, but is now reassessed as an aculeate wasp of uncertain position rather than a true bee.\n",
      "citation": "Ren, D., Labandeira, C.C., Santiago-Blay, J.A. et al. (2009). \"A Probable Pollination Mode Before Angiosperms: Eurasian, Long-Proboscid Scorpionflies.\" Science, 326(5954), 840-847. Poinar, G.O. & Danforth, B.N. (2006). \"A fossil bee from Early Cretaceous Burmese amber.\" Science, 314(5799), 614 (original bee claim, contested reclassification).\n"
    },
    {
      "id": "flowering-plants",
      "label": "Flowering plants",
      "kind": "moment",
      "tMin": 125000000.0,
      "tMax": 133000000.0,
      "t": 130000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.75,
      "description": "The oldest undisputed flowering plants (Montsechia vidalii, Archaefructus) appear in Early Cretaceous lake deposits. A disputed claim of Middle Triassic angiosperm-like pollen (~247-242 Ma) from the Alps has not been widely accepted, so the timing of angiosperm origin well before the Cretaceous remains unresolved.\n",
      "citation": "Gomez, B. et al. (2015). \"Montsechia, an ancient aquatic angiosperm.\" PNAS, 112(35), 10985-10988 (~130 Ma, Barremian). Earliest undisputed angiosperm pollen spans the Hauterivian-Barremian, ~132.9-125 Ma.\n"
    },
    {
      "id": "birds-origin",
      "label": "First birds",
      "kind": "moment",
      "tMin": 148500000.0,
      "tMax": 150800000.0,
      "t": 149650000.0,
      "tags": [
        "life"
      ],
      "importance": 0.6,
      "description": "Archaeopteryx lithographica, from the Solnhofen limestone of Bavaria, is the earliest widely accepted bird — a feathered, winged theropod bridging non-avian dinosaurs and modern birds.\n",
      "citation": "Foth, C. & Rauhut, O.W.M. (2017). \"Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs.\" BMC Evolutionary Biology, 17, 236. Archaeopteryx horizon within the Solnhofen Limestone (Late Jurassic, Tithonian), ~150.8-148.5 Ma.\n"
    },
    {
      "id": "end-triassic-extinction",
      "label": "End-Triassic mass extinction",
      "kind": "period",
      "tMin": 201000000.0,
      "tMax": 201800000.0,
      "tags": [
        "catastrophe"
      ],
      "importance": 0.8,
      "description": "One of the \"Big Five\", and the one that hands the world to the dinosaurs. Its trigger is the Central Atlantic Magmatic Province, erupting as Pangaea begins to tear open along the line that becomes the Atlantic. The dying falls hardest on the crurotarsans — the crocodile-line archosaurs that had dominated Triassic landscapes and kept dinosaurs in a minor role for some 30 million years — and takes the last conodonts with it. Dinosaurs inherit the emptied niches and hold them for the next 135 million years.\n",
      "citation": "Blackburn, T.J. et al. (2013). \"Zircon U-Pb Geochronology Links the End-Triassic Extinction with the Central Atlantic Magmatic Province.\" Science, 340(6135), 941-945.\n"
    },
    {
      "id": "manicouagan-impact-crater",
      "label": "Manicouagan impact",
      "kind": "moment",
      "tMin": 213000000.0,
      "tMax": 215000000.0,
      "t": 214000000.0,
      "tags": [
        "catastrophe"
      ],
      "importance": 0.35,
      "description": "A ~5 km asteroid strikes what is now Quebec, Canada, excavating a crater originally about 100 km across — Earth's sixth-largest confirmed impact structure, now the ring-shaped Manicouagan Reservoir. At 214 Ma it long predates the end-Triassic extinction (201 Ma, below) by too wide a margin to be its trigger, a hypothesis once proposed and since abandoned; a contested link to a smaller, localised Late Triassic faunal turnover remains debated.\n",
      "citation": "Hodych, J.P. & Dunning, G.R. (1992). \"Did the Manicouagan impact trigger end-of-Triassic mass extinction?\" Geology, 20(1), 51-54. Cross-checked live via Wikipedia, \"Manicouagan Reservoir\" (accessed 2026-09-22), which cites a more recent Ramezani et al. U-Pb zircon age of 215.56 +/- 0.05 Ma.\n"
    },
    {
      "id": "mammals-origin",
      "label": "First mammals",
      "kind": "moment",
      "tMin": 205000000.0,
      "tMax": 225000000.0,
      "t": 215000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.55,
      "description": "The earliest mammaliaforms — small, likely nocturnal insectivores — diverge from cynodont therapsids around the Triassic-Jurassic boundary.\n",
      "citation": "Lucas, S.G. & Luo, Z. (1993). \"Adelobasileus from the Upper Triassic of West Texas: the oldest mammal.\" Journal of Vertebrate Paleontology, 13(3), 309-334 (~225 Ma). Kermack, K.A., Mussett, F. & Rigney, H.W. (1981) for Morganucodon, ~205 Ma.\n"
    },
    {
      "id": "pterosaurs-origin",
      "label": "First pterosaurs",
      "kind": "moment",
      "tMin": 210000000.0,
      "tMax": 227000000.0,
      "t": 215000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.6,
      "description": "The first vertebrates to fly under their own power: the oldest definite pterosaurs, such as Eudimorphodon from the Norian Zorzino Limestone of northern Italy, are ~215 million years old and already fully adapted for flight. Their closest known relatives, the lagerpetids, point to an earlier origin; a Carnian-Norian specimen from Brazil (Faxinalipterus) is of contested affinity.\n",
      "citation": "Kligman, B.T. et al. (2025). \"Unusual bone bed reveals a vertebrate community with pterosaurs and turtles in equatorial Pangaea before the end-Triassic extinction.\" PNAS, 122(29), e2505513122. doi:10.1073/pnas.2505513122 (with its Smithsonian release: oldest known pterosaur fossils ~215 Ma, in Europe). Wild, R. (1978), Eudimorphodon ranzii, Calcare di Zorzino, Norian (venue UNVERIFIED). Ezcurra, M.D. et al. (2020). \"Enigmatic dinosaur precursors bridge the gap to the origin of Pterosauria.\" Nature, 588, 445-449. Norian base ~227 Ma per the ICS International Chronostratigraphic Chart v2024/12.\n"
    },
    {
      "id": "dinosaurs",
      "label": "First dinosaurs",
      "kind": "moment",
      "tMin": 231000000.0,
      "tMax": 243000000.0,
      "t": 231000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.8,
      "description": "The oldest unambiguous dinosaurs (Eoraptor, Herrerasaurus) appear in the Ischigualasto Formation of Argentina ~231 Ma. Contested: the fragmentary Nyasasaurus parringtoni, if correctly identified as a dinosaur rather than a close relative, would push the origin back to ~243 Ma.\n",
      "citation": "Martinez, R.N. et al. (2011). \"A basal dinosaur from the dawn of the dinosaur era in southwestern Pangaea.\" Science, 331(6014), 206-210 (Eoraptor, ~231 Ma). Nesbitt, S.J. et al. (2013). \"The oldest dinosaur? A Middle Triassic dinosauriform from Tanzania.\" Biology Letters, 9(1), 20120949 (Nyasasaurus, contested, ~243 Ma).\n"
    },
    {
      "id": "ichthyosaurs-origin",
      "label": "First ichthyosaurs",
      "kind": "moment",
      "tMin": 248000000.0,
      "tMax": 251900000.0,
      "t": 250000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.5,
      "description": "Reptiles return to the sea soon after the end-Permian extinction: tail vertebrae of an already fully oceanic, ~3 m ichthyosaur from Smithian rocks of Spitsbergen, ~250 Ma, are the oldest yet found, ahead of the small, possibly amphibious Cartorhynchus and Chaohusaurus of China ~248 Ma. So derived a form so early implies the lineage began earlier; whether it arose before the extinction itself is contested.\n",
      "citation": "Kear, B.P., Engelschion, V.S., Hammer, O., Roberts, A.J. & Hurum, J.H. (2023). \"Earliest Triassic ichthyosaur fossils push back oceanic reptile origins.\" Current Biology, 33(5), R178-R179. doi:10.1016/j.cub.2022.12.053. Motani, R. et al. (2015). \"A basal ichthyosauriform with a short snout from the Lower Triassic of China.\" Nature, 517(7535), 485-488 (Cartorhynchus, ~248 Ma). Permian-Triassic boundary 251.902 Ma per the ICS International Chronostratigraphic Chart v2024/12.\n"
    },
    {
      "id": "permian-extinction",
      "label": "End-Permian mass extinction",
      "kind": "period",
      "tMin": 251880000.0,
      "tMax": 251941000.0,
      "tags": [
        "catastrophe"
      ],
      "importance": 1.0,
      "description": "The most severe mass extinction in Earth's history eliminates over 90% of marine species and roughly 70% of terrestrial vertebrate genera, over an interval as short as ~60,000 years — one of the most precisely dated events in deep time.\n",
      "citation": "Burgess, S.D., Bowring, S. & Shen, S.Z. (2014). \"High-precision timeline for Earth's most severe extinction.\" PNAS, 111(9), 3316-3321. Extinction interval bracketed between 251.941 +/- 0.037 Ma and 251.880 +/- 0.031 Ma at the Meishan GSSP, Zhejiang, China.\n"
    },
    {
      "id": "siberian-traps",
      "label": "Siberian Traps eruptions",
      "kind": "period",
      "tMin": 250000000.0,
      "tMax": 254000000.0,
      "tags": [
        "catastrophe",
        "earth-climate"
      ],
      "importance": 0.7,
      "description": "One of the largest volcanic events in Earth's history: roughly two million years of flood-basalt eruptions across Siberia, releasing enormous volumes of CO2, sulphur and halogens. Widely held to be the principal driver of the end-Permian mass extinction (below), through some combination of runaway warming, ocean acidification and anoxia.\n",
      "citation": "Burgess, S.D. & Bowring, S.A. (2015). \"High-precision geochronology confirms voluminous magmatism before, during, and after Earth's most severe extinction.\" Science Advances, 1(7), e1500470. Kamo, S.L. et al. (2003). \"Rapid eruption of Siberian flood-volcanic rocks and evidence for coincidence with the Permian-Triassic boundary and mass extinction at 251 Ma.\" Earth and Planetary Science Letters, 214(1-2), 75-91.\n"
    },
    {
      "id": "pangaea-supercontinent",
      "label": "Pangaea assembles and rifts apart",
      "kind": "period",
      "tMin": 175000000.0,
      "tMax": 335000000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.7,
      "description": "Nearly all of Earth's continental crust collides into the single supercontinent Pangaea through the Carboniferous and into the Permian, then spends over 150 million years slowly rifting apart into the modern continents, opening the Atlantic and Indian Oceans. Assembly begins around 335 Ma; when it counts as complete is itself debated, with estimates ranging from the Early Permian (~300 Ma) to as late as ~270 Ma once Siberia's collision is counted. Breakup begins near the Triassic-Jurassic boundary (~200 Ma); near-total fragmentation is dated to ~175 Ma by some sources and not until the Middle Jurassic (~160 Ma) by others.\n",
      "citation": "Scotese, C.R. (2004). \"A Continental Drift Flipbook.\" Journal of Geology, 112(6), 729-741 (assembly by ~335-320 Ma). Torsvik, T.H. & Cocks, L.R.M. (2017). Earth History and Palaeogeography. Cambridge University Press (breakup onset ~200 Ma, near-total fragmentation by ~175 Ma). Cross-checked live via Wikipedia, \"Pangaea\" (2026-09-14), which instead names Rogers, J.J.W. & Santosh, M. (2004), Continents and Supercontinents (Oxford University Press), for a ~335 Ma assembly start / ~300 Ma completion and a breakup running to the Middle Jurassic (~160 Ma) — the same broad shape, different precise bounds; UNVERIFIED which pair of sources a curator should anchor the interval on.\n"
    },
    {
      "id": "gymnosperm-radiation",
      "label": "Conifers and gymnosperms radiate",
      "kind": "period",
      "tMin": 290000000.0,
      "tMax": 310000000.0,
      "tags": [
        "life",
        "earth-climate"
      ],
      "importance": 0.35,
      "description": "As the coal-swamp lycopsids retreat with the Carboniferous rainforest collapse (above), walchian conifers (Voltziales, e.g. Walchia) spread across drier ground. They are among the earliest conifers, which first appear in the Middle Pennsylvanian, before this interval; it marks their spread within a broader seed-plant (gymnosperm) radiation that comes to dominate Permian and Triassic vegetation.\n",
      "citation": "UNVERIFIED: no primary source confirmed yet. Walchian conifer ranges were checked only against encyclopaedia summaries (Wikipedia, \"Walchia\" and \"Voltziales\"); Looy, C.V. & Duijnstee, I.A.P. (2020) on voltzialean cone evolution has its authors and year confirmed but not its journal or volume.\n"
    },
    {
      "id": "carboniferous-rainforest-collapse",
      "label": "Carboniferous rainforest collapse",
      "kind": "moment",
      "tMin": 300000000.0,
      "tMax": 307000000.0,
      "t": 305000000.0,
      "tags": [
        "life",
        "earth-climate"
      ],
      "importance": 0.5,
      "description": "Around 305 Ma the lycopsid-dominated coal-swamp rainforests of equatorial Euramerica fragment into isolated refugia and give way to tree-fern-dominated vegetation as the climate dries; in Cathaysia (China) such rainforests persist until the end of the Permian. The scale and ecological effects are contested.\n",
      "citation": "Sahney, S., Benton, M.J. & Falcon-Lang, H.J. (2010). \"Rainforest collapse triggered Carboniferous tetrapod diversification in Euramerica.\" Geology, 38(12), 1079-1082. Dunne, E.M. et al. (2018). Proceedings of the Royal Society B (contests the effect on tetrapod diversity). Montanez, I.P. et al. (2007). \"CO2-forced climate and vegetation instability during late Paleozoic deglaciation.\" Science, 315(5808), 87-91.\n"
    },
    {
      "id": "late-paleozoic-ice-age",
      "label": "Late Paleozoic Ice Age",
      "kind": "period",
      "tMin": 255000000.0,
      "tMax": 360000000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.6,
      "description": "Repeated glacial-interglacial cycles build and melt ice sheets across Gondwana for roughly a hundred million years, ice centres migrating from South America and Africa early on to a final Australian centre as Gondwana drifts across the South Pole. The ice age proper is usually dated from ~335-330 Ma, though isolated, more transient glacial episodes reach back to ~360 Ma (hence the wide t_max); its last alpine glaciers melt in eastern Australia around 255 Ma. Contested: whether the record reflects one continuous glaciation or as many as 25 separate, diachronous Gondwanan ice sheets is actively debated.\n",
      "citation": "Montanez, I.P. & Poulsen, C.J. (2013). \"The Late Paleozoic Ice Age: An Evolving Paradigm.\" Annual Review of Earth and Planetary Sciences, 41, 629-656. Scotese, C.R. et al. (2021). \"Phanerozoic paleotemperatures: The earth's changing climate during the last 540 million years.\" Earth-Science Reviews, 215, 103503. Overall 360-255 Ma bracket and the one-event-vs-many-ice-sheets debate corroborated live via Wikipedia, \"Late Paleozoic icehouse\" (2026-09-14), which cites Rosa & Isbell (2021) and Kent & Muttoni (2020) for the same 360-255 Ma figures and Montanez (2021) for the ~335-330 Ma proper-onset date.\n"
    },
    {
      "id": "amniotes",
      "label": "First amniotes",
      "kind": "moment",
      "tMin": 307000000.0,
      "tMax": 358900000.0,
      "t": 312500000.0,
      "tags": [
        "life"
      ],
      "importance": 0.7,
      "description": "The amniotic egg allows vertebrates to reproduce away from standing water. Hylonomus lyelli (~318-307 Ma) is the oldest uncontroversial amniote. Contested: fossil trackways from the Snowy Plains Formation, Victoria, Australia, attributed to a crown-group amniote with clawed feet and dated to the early Tournaisian (~358.9-354 Ma), would push the origin of crown Amniota back by 35-40 Myr if the attribution holds.\n",
      "citation": "Carroll, R.L. (1964). \"The earliest reptiles.\" Zoological Journal of the Linnean Society, 45, 61-83 (Hylonomus lyelli). Contested pushback: Long, J.A. et al. (2025). \"Earliest amniote tracks recalibrate the timeline of tetrapod evolution.\" Nature, 641, 1193-1200 (Snowy Plains Formation track-bearing slab).\n"
    },
    {
      "id": "late-devonian-extinction",
      "label": "Late Devonian mass extinction",
      "kind": "period",
      "tMin": 358860000.0,
      "tMax": 372150000.0,
      "tags": [
        "catastrophe"
      ],
      "importance": 0.75,
      "description": "Two extinction pulses bracket the Late Devonian: the Kellwasser event at the Frasnian-Famennian boundary (~372.15 Ma), then the Hangenberg event ending the Devonian entirely (~358.86 Ma) — together one of the \"Big Five,\" severely reducing reef-building and marine vertebrate diversity and triggering marked body-size reduction among surviving fish lineages.\n",
      "citation": "Becker, R.T. & House, M.R. \"Kellwasser Events and goniatite successions in the Devonian of the Montagne Noire.\" Courier Forschungsinstitut Senckenberg, 169, 45-77 (UNVERIFIED: the year is given as 1986 but looks inconsistent with that volume). Sallan, L. & Galimberti, A.K. (2015). \"Body-size reduction in vertebrates following the end-Devonian mass extinction.\" Science, 350(6262), 812-815. Percival, L.M.E. et al. (2018). \"Precisely dating the Frasnian-Famennian boundary.\" Scientific Reports, 8, 9578 (UNVERIFIED: bibliographic line not confirmed against its DOI page).\n"
    },
    {
      "id": "first-seed-plants",
      "label": "First seed plants",
      "kind": "moment",
      "tMin": 360000000.0,
      "tMax": 370000000.0,
      "t": 370000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.55,
      "description": "Elkinsia polymorpha, a seed fern from the Late Devonian of West Virginia, bears the oldest well-documented seeds: an integumented ovule enclosed in a cupule, freeing reproduction from the standing water that spore-dispersal required. The precursor Runcaria (~385 Ma, Middle Devonian, Belgium) shows the integument evolving slightly earlier, without yet being a true seed.\n",
      "citation": "Rothwell, G.W., Scheckler, S.E. & Gillespie, W.H. (1989). \"Elkinsia gen. nov., a Late Devonian gymnosperm with cupulate ovules.\" Botanical Gazette, 150(2), 170-189. UNVERIFIED: author, year and the Elkinsia/Late-Devonian/~370 Ma facts were confirmed live; the title, journal, volume and pages were not — see sources/events-core/README.md \"Verification method\".\n"
    },
    {
      "id": "first-forests",
      "label": "First forests",
      "kind": "moment",
      "tMin": 378000000.0,
      "tMax": 393000000.0,
      "t": 390000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.55,
      "description": "The first forests appear in the Middle Devonian. The oldest known, ~390 Ma in Somerset, England, is a stand of Calamophyton, a small cladoxylopsid tree; at Gilboa, New York, slightly younger stumps preserve dense stands of the taller cladoxylopsid Eospermatopteris. Archaeopteris, the first tree with true wood and fern-like leafy branches, is present by ~385 Ma and dominates Late Devonian forests.\n",
      "citation": "Davies, N.S., McMahon, W.J. & Berry, C.M. (2024). \"Earth's earliest forest: fossilized trees and vegetation-induced sedimentary structures from the Middle Devonian (Eifelian) Hangman Sandstone Formation, Somerset and Devon, SW England.\" Journal of the Geological Society, doi:10.1144/jgs2023-204. Stein, W.E., Mannolini, F., Hernick, L.V., Landing, E. & Berry, C.M. (2007). \"Giant cladoxylopsid trees resolve the enigma of the Earth's earliest forest stumps at Gilboa.\" Nature, 446(7138), 904-907.\n"
    },
    {
      "id": "tetrapods",
      "label": "First tetrapods",
      "kind": "moment",
      "tMin": 365000000.0,
      "tMax": 395000000.0,
      "t": 390500000.0,
      "tags": [
        "life"
      ],
      "importance": 0.85,
      "description": "The oldest evidence of tetrapods — four-limbed vertebrates capable of terrestrial locomotion. Trackways from Zachelmie, Poland predate the oldest body fossils (Ichthyostega, Acanthostega) by roughly 20-30 Myr.\n",
      "citation": "Niedzwiedzki, G. et al. (2010). \"Tetrapod trackways from the early Middle Devonian period of Poland.\" Nature, 463, 43-48 (recalibrated to ~390-391 Ma against GTS2012). Ahlberg, P.E. & Clack, J.A. (2006) for Ichthyostega/Acanthostega body fossils, ~365 Ma, Late Devonian.\n"
    },
    {
      "id": "insects",
      "label": "First insects",
      "kind": "moment",
      "tMin": 396000000.0,
      "tMax": 411000000.0,
      "t": 409000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.5,
      "description": "Rhyniognatha hirsti, from the Rhynie chert, is the specimen most commonly cited as the oldest insect, based on mandible structure some interpret as diagnostic of a winged insect. Contested: the fragmentary specimen has also been reinterpreted as a myriapod rather than an insect.\n",
      "citation": "Engel, M.S. & Grimaldi, D.A. (2004). \"New light shed on the oldest insect.\" Nature, 427, 627-630. Rhynie chert radiometrically dated to ~407-411 Ma (Parry, S.F. et al. 2011, Geology). Reinterpretation: Haug, C. & Haug, J.T. (2017). \"The presumed oldest flying insect: more likely a myriapod?\" PeerJ, 5, e3402.\n"
    },
    {
      "id": "end-ordovician-extinction",
      "label": "End-Ordovician mass extinction",
      "kind": "period",
      "tMin": 440000000.0,
      "tMax": 445000000.0,
      "tags": [
        "catastrophe"
      ],
      "importance": 0.8,
      "description": "One of the \"Big Five\" mass extinctions, eliminating roughly 85% of marine species in two pulses: a first pulse tied to rapid Gondwanan glaciation and sea-level fall, a second later in the Hirnantian, tied to widespread ocean anoxia and euxinia that persisted into the earliest Silurian. Bracketing dates carry real uncertainty; the two-pulse structure is well established.\n",
      "citation": "Sheehan, P.M. (2001). \"The Late Ordovician Mass Extinction.\" Annual Review of Earth and Planetary Sciences, 29(1), 331-364. Stockey, R.G. et al. (2020). \"Persistent global marine euxinia in the early Silurian.\" Nature Communications, 11(1), 1804.\n"
    },
    {
      "id": "land-plants",
      "label": "Land plants colonise land",
      "kind": "moment",
      "tMin": 425000000.0,
      "tMax": 470000000.0,
      "t": 447500000.0,
      "tags": [
        "life"
      ],
      "importance": 0.8,
      "description": "Embryophytes (land plants) colonise the terrestrial surface. Contested: the oldest fossil evidence is liverwort-like cryptospores at ~470 Ma (Dapingian, Ordovician), while the oldest unambiguous vascular macrofossils (Cooksonia) are ~425 Ma (Silurian).\n",
      "citation": "Rubinstein, C.V. et al. (2010). \"Early Middle Ordovician evidence for land plants in Argentina (eastern Gondwana).\" New Phytologist, 188(2), 365-369. Edwards, D., Fanning, U. & Richardson, J.B. (1994) for Cooksonia macrofossils, Silurian, ~425 Ma.\n"
    },
    {
      "id": "great-ordovician-biodiversification",
      "label": "Great Ordovician Biodiversification Event",
      "kind": "period",
      "tMin": 467330000.0,
      "tMax": 497050000.0,
      "tags": [
        "life"
      ],
      "importance": 0.6,
      "description": "Marine animal diversity rises sharply through the Ordovician as reef-building, suspension-feeding and pelagic clades radiate, tripling the number of marine families and replacing the sparser Cambrian fauna with a richer, more modern-looking Paleozoic one. Neither instantaneous nor globally synchronous — different clades diversify at different times in different places.\n",
      "citation": "Fan, J. et al. (2020). \"A high-resolution summary of Cambrian to Early Triassic marine invertebrate biodiversity.\" Science, 367(6475), 272-277.\n"
    },
    {
      "id": "cambrian-explosion",
      "label": "Cambrian explosion",
      "kind": "period",
      "tMin": 521000000.0,
      "tMax": 538800000.0,
      "tags": [
        "life"
      ],
      "importance": 1.0,
      "description": "Most modern animal phyla appear in the fossil record within a geologically short interval at the base of the Cambrian, as hard skeletons, complex eyes and burrowing behaviour become widespread for the first time.\n",
      "citation": "Base of the Cambrian System (Ediacaran-Cambrian boundary, Fortune Head GSSP, Newfoundland) = 538.8 +/- 0.2 Ma, per the ICS International Chronostratigraphic Chart v2024/12. Erwin, D.H. & Valentine, J.W. (2013). The Cambrian Explosion: The Construction of Animal Biodiversity. Roberts and Company (main diversification pulse ends within Cambrian Stage 3, ~521 Ma).\n"
    },
    {
      "id": "ediacaran-biota",
      "label": "Ediacaran biota",
      "kind": "period",
      "tMin": 538800000.0,
      "tMax": 571000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.75,
      "description": "The Ediacara Biota — the first macroscopic, complex, soft-bodied multicellular organisms — appear worldwide (Avalon assemblage, ~571 Ma) and persist until the Ediacaran-Cambrian boundary. The interval here spans the biota's known stratigraphic range, not date uncertainty about a single origin event.\n",
      "citation": "Narbonne, G.M. (2005). \"The Ediacara Biota: Neoproterozoic origin of animals and their ecosystems.\" Annual Review of Earth and Planetary Sciences, 33, 421-442. Top of Ediacaran Period (Fortune Head GSSP) = 538.8 +/- 0.2 Ma per the ICS International Chronostratigraphic Chart v2024/12.\n"
    },
    {
      "id": "gondwana-supercontinent-assembly",
      "label": "Gondwana assembles",
      "kind": "period",
      "tMin": 530000000.0,
      "tMax": 600000000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.55,
      "description": "Fragments scattered by Rodinia's breakup (above) — Africa, South America, Madagascar, India, Australia and Antarctica — collide back together as the Mozambique Ocean closes, in the overlapping Brasiliano and Kuunga orogenies of the Pan-African orogenic episode, c. 600-530 Ma. An earlier phase, the East African Orogeny (c. 800-650 Ma), had already stitched together Gondwana's eastern cratons. Gondwana persists as the southern half of Pangaea (below) until that supercontinent's own breakup.\n",
      "citation": "Meert, J.G. & Van der Voo, R. (1997). \"The assembly of Gondwana 800-550 Ma.\" Journal of Geodynamics, 23(3-4), 223-235. Meert, J.G. (2003). \"A synopsis of events related to the assembly of eastern Gondwana.\" Tectonophysics, 362(1-4), 1-40. Cross-checked live via Wikipedia, \"Gondwana\" (accessed 2026-09-22).\n"
    },
    {
      "id": "acraman-impact-crater",
      "label": "Acraman impact",
      "kind": "moment",
      "tMin": 570000000.0,
      "tMax": 590000000.0,
      "t": 580000000.0,
      "tags": [
        "catastrophe"
      ],
      "importance": 0.35,
      "description": "An asteroid strikes the Gawler Ranges of South Australia, excavating a crater up to 90 km across — among the largest known Precambrian impacts. Unlike most events in this file, its age comes not from dating the crater itself (deeply eroded, its melt long gone) but from the stratigraphic position of a shocked-ejecta horizon within the Bunyeroo Formation, several hundred kilometres away.\n",
      "citation": "Williams, G.E. & Wallace, M.W. (2003). \"The Acraman asteroid impact, South Australia: magnitude and implications for the late Vendian environment.\" Journal of the Geological Society, 160(4), 545-554. Grey, K., Walter, M.R. & Calver, C.R. (2003). \"Neoproterozoic biotic diversification: Snowball Earth, GOE, and the rise of bilaterians.\" Geology, 31(6), 459-462 (ejecta-horizon age constraint, ~580 Ma).\n"
    },
    {
      "id": "snowball-earth",
      "label": "Snowball Earth glaciations",
      "kind": "period",
      "tMin": 635000000.0,
      "tMax": 720000000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.85,
      "description": "Two near-global glaciations — the Sturtian (~717-661 Ma) and Marinoan (ending 635 Ma; ~4-15 Myr, duration contested) — bracket the Cryogenian Period, with geological evidence of ice reaching equatorial latitudes (\"Snowball Earth\"). Onset and termination ages carry real uncertainty.\n",
      "citation": "Prave, A.R. et al. (2016). \"A new rock-based definition for the Cryogenian Period (circa 720-635 Ma).\" Episodes, 39(2), 1-7. Base and top ages of the Cryogenian System per the ICS International Chronostratigraphic Chart v2024/12. Effect windows: Rooney, A.D., Strauss, J.V., Brandon, A.D. & Macdonald, F.A. (2015). \"A Cryogenian chronology: Two long-lasting synchronous Neoproterozoic glaciations.\" Geology, 43, 459-462 (Sturtian, 56 Myr). Tasistro-Hart, A.R., Macdonald, F.A., Crowley, J.L. & Schmitz, M.D. (2025). \"Four-million-year Marinoan snowball shows multiple routes to deglaciation.\" PNAS, 122(18), e2418281122 (Marinoan, duration contested).\n",
      "effect": {
        "kind": "ice-shell",
        "windows": [
          {
            "tMin": 661000000.0,
            "tMax": 717000000.0
          },
          {
            "tMin": 635000000.0,
            "tMax": 639000000.0
          }
        ]
      }
    },
    {
      "id": "rodinia-supercontinent",
      "label": "Rodinia assembles and rifts apart",
      "kind": "period",
      "tMin": 633000000.0,
      "tMax": 1300000000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.65,
      "description": "Nearly every continental block then in existence collides together through worldwide orogenic events between about 1.3 and 0.9 Ga, forming Rodinia. Rifting begins by around 825-750 Ma and is largely complete by 750-633 Ma, as the continents that once bordered Laurentia scatter and later regroup as Gondwana (below); the rifting's silicate weathering is one leading hypothesis for the runaway cooling behind the Cryogenian Snowball Earth glaciations, which follow almost immediately.\n",
      "citation": "Li, Z.X. et al. (2008). \"Assembly, configuration, and break-up history of Rodinia: A synthesis.\" Precambrian Research, 160(1-2), 179-210. Cross-checked live via Wikipedia, \"Rodinia\" (accessed 2026-09-22).\n"
    },
    {
      "id": "first-seaweeds",
      "label": "Early green seaweeds",
      "kind": "moment",
      "tMin": 790000000.0,
      "tMax": 1000000000.0,
      "t": 1000000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.4,
      "description": "Proterocladus antiquus, a multicellular chlorophyte (green alga) from the Nanfen Formation, China, is described from over 1,000 specimens showing branching thalli, varied cell shapes and asexual resting spores — a fully multicellular seaweed body plan roughly a billion years old. Red algae (Bangiomorpha, ~1.05 Ga) had already become multicellular slightly earlier.\n",
      "citation": "Tang, Q., Pang, K., Yuan, X. & Xiao, S. (2020). \"A one-billion-year-old multicellular chlorophyte.\" Nature Ecology & Evolution, 4(4), 543-549.\n"
    },
    {
      "id": "multicellularity-sexual-reproduction",
      "label": "Complex multicellularity and sex",
      "kind": "moment",
      "tMin": 1030000000.0,
      "tMax": 1064000000.0,
      "t": 1047000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.55,
      "description": "Bangiomorpha pubescens, a red alga from Arctic Canada, is the oldest fossil with differentiated reproductive cells and complex multicellular organisation — the earliest direct evidence of eukaryotic sexual reproduction.\n",
      "citation": "Gibson, T.M. et al. (2018). \"Precise age of Bangiomorpha pubescens dates the origin of eukaryotic photosynthesis.\" Geology, 46(2), 135-138. Age 1047 +/- 17 Ma via Re-Os dating.\n"
    },
    {
      "id": "eukaryotes-origin",
      "label": "Eukaryotes originate",
      "kind": "moment",
      "tMin": 1600000000.0,
      "tMax": 2100000000.0,
      "t": 1600000000.0,
      "tags": [
        "life"
      ],
      "importance": 0.65,
      "description": "The lineage bearing a nucleus and internal membrane-bound organelles diverges from other life. Contested: candidate fossils (the Francevillian Biota, Gabon) are dated to 2.1 Ga, but the oldest fossils with unambiguous crown-eukaryote features are ~1.6 Ga, closer to molecular-clock estimates for the last eukaryotic common ancestor.\n",
      "citation": "El Albani, A. et al. (2010). \"Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago.\" Nature, 466, 100-104 (contested, 2.1 Ga). Bengtson, S. et al. (2017). \"Three-dimensional preservation of cellular and subcellular structures suggests 1.6 billion-year-old crown-group red algae.\" PLOS Biology, 15(3), e2000735.\n"
    },
    {
      "id": "nuna-columbia-supercontinent",
      "label": "Nuna/Columbia assembles and rifts apart",
      "kind": "period",
      "tMin": 1200000000.0,
      "tMax": 2100000000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.55,
      "description": "One of the first supercontinents reconstructable from the rock record — variously called Nuna or Columbia, with reconstructions differing in exact extent and timing. Global-scale collisional orogens weld its core together from roughly 2.1-1.8 Ga, with continued accretionary growth at its margins out to about 1.6-1.5 Ga. Breakup is diachronous, beginning as early as 1.6 Ga and largely complete by 1.3-1.2 Ga, scattering fragments that later reassemble as Rodinia (below).\n",
      "citation": "Zhao, G., Cawood, P.A., Wilde, S.A. & Sun, M. (2002). \"Review of global 2.1-1.8 Ga orogens: implications for a pre-Rodinia supercontinent.\" Earth-Science Reviews, 59(1-2), 125-162. Rogers, J.J.W. & Santosh, M. (2002). \"Configuration of Columbia, a Mesoproterozoic supercontinent.\" Gondwana Research, 5(1), 5-22. Zhao, G., Sun, M., Wilde, S.A. & Li, S. (2004). \"A Paleo-Mesoproterozoic supercontinent: assembly, growth and breakup.\" Earth-Science Reviews, 67(1-2), 91-123. Cross-checked live via Wikipedia, \"Columbia (supercontinent)\" (accessed 2026-09-22).\n"
    },
    {
      "id": "sudbury-impact-crater",
      "label": "Sudbury impact",
      "kind": "moment",
      "tMin": 1848000000.0,
      "tMax": 1851000000.0,
      "t": 1849500000.0,
      "tags": [
        "catastrophe"
      ],
      "importance": 0.4,
      "description": "An asteroid or comet roughly 10-15 km across strikes what is now Ontario, Canada, excavating the second-largest verified impact crater on Earth, originally about 130 km across. Its solidified melt sheet, the Sudbury Igneous Complex, later differentiated into one of the world's largest nickel-copper-platinum group element ore deposits.\n",
      "citation": "Davis, D.W. (2008). \"Sub-million-year age resolution of Precambrian igneous events by thermal extraction-thermal ionization mass spectrometer Pb dating of zircon: Application to crystallization of the Sudbury impact melt sheet.\" Geology, 36(5), 383-386.\n"
    },
    {
      "id": "vredefort-impact-crater",
      "label": "Vredefort impact",
      "kind": "moment",
      "tMin": 2019000000.0,
      "tMax": 2027000000.0,
      "t": 2023000000.0,
      "tags": [
        "catastrophe"
      ],
      "importance": 0.4,
      "description": "An asteroid strikes what is now the Free State, South Africa, excavating the largest verified impact crater on Earth — an original structure some 170-280 km across, now eroded to the central Vredefort Dome. A 2022 re-analysis of the crater's formation revised the impactor upward to roughly 20-25 km across, larger than the impactor behind the Chicxulub crater that ends the non-avian dinosaurs (k-pg-impact, below).\n",
      "citation": "Kamo, S.L., Reimold, W.U., Krogh, T.E. & Colliston, W.P. (1996). \"A 2.023 Ga age for the Vredefort impact event and a first report of shock metamorphosed zircons in pseudotachylitic breccias and Granophyre.\" Earth and Planetary Science Letters, 144(3-4), 369-387. Allen, N.H. et al. (2022). \"A Revision of the Formation Conditions of the Vredefort Crater.\" Journal of Geophysical Research: Planets, 127(10), e2022JE007186.\n"
    },
    {
      "id": "great-oxidation-event",
      "label": "Great Oxidation Event",
      "kind": "period",
      "tMin": 2100000000.0,
      "tMax": 2400000000.0,
      "tags": [
        "earth-climate",
        "life"
      ],
      "importance": 0.95,
      "description": "Atmospheric oxygen rises by orders of magnitude as cyanobacterial photosynthesis overwhelms reducing sinks in the crust and ocean — the first permanent oxygenation of Earth's atmosphere, ending the anoxic Archean.\n",
      "citation": "Lyons, T.W., Reinhard, C.T. & Planavsky, N.J. (2014). \"The rise of oxygen in Earth's early ocean and atmosphere.\" Nature, 506, 307-315.\n"
    },
    {
      "id": "banded-iron-formations",
      "label": "Banded iron formations peak",
      "kind": "period",
      "tMin": 1850000000.0,
      "tMax": 2800000000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.35,
      "description": "Dissolved iron in the anoxic Archean ocean is oxidised by cyanobacterial oxygen and precipitates as banded iron formations, the main geochemical record of early oxygenation. Deposition peaks in the late Archean (2.8-2.5 Ga) with a second pulse around 1.85 Ga, after which the deposits largely stop — marking, it is generally argued, when the deep ocean itself finally became oxygenated.\n",
      "citation": "Cloud, P. (1973). \"Paleoecological Significance of the Banded Iron-Formation.\" Economic Geology, 68(7), 1135-1143. Holland, H.D. (2006). \"The oxygenation of the atmosphere and oceans.\" Philosophical Transactions of the Royal Society B, 361(1470), 903-915.\n"
    },
    {
      "id": "huronian-glaciation",
      "label": "Huronian glaciation",
      "kind": "period",
      "tMin": 2220000000.0,
      "tMax": 2450000000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 0.6,
      "description": "Earth's first known ice ages: three glacial diamictites (Ramsay Lake, Bruce and Gowganda formations) in the Huronian Supergroup of Ontario, deposited between ~2.45 Ga and the 2.22 Ga Nipissing diabase that cuts them, broadly coeval with the Great Oxidation Event as rising oxygen destroyed a methane greenhouse. Contested: whether any of them was global (a \"snowball\"), and how they correlate with South Africa's Makganyene glaciation, dated to ~2.3-2.22 Ga by Kopp et al. (2005) but to before ~2.43 Ga by Gumsley et al. (2017).\n",
      "citation": "Sekine, Y. et al. (2011). \"Osmium evidence for synchronicity between a rise in atmospheric oxygen and Palaeoproterozoic deglaciation.\" Nature Communications, 2, 502 (Huronian stratigraphy; depositional age ~2.45-2.217 Ga, Nipissing diabase 2217 +/- 9 Ma). Kopp, R.E., Kirschvink, J.L., Hilburn, I.A. & Nash, C.Z. (2005). \"The Paleoproterozoic snowball Earth: A climate disaster triggered by the evolution of oxygenic photosynthesis.\" PNAS, 102(32), 11131-11136. doi:10.1073/pnas.0504878102. Gumsley, A.P. et al. (2017). \"Timing and tempo of the Great Oxidation Event.\" PNAS, 114(8), 1811-1816. doi:10.1073/pnas.1608824114 (first Paleoproterozoic global glaciation and GOE onset between ~2,460 and 2,426 Ma).\n"
    },
    {
      "id": "origin-of-photosynthesis",
      "label": "Oxygenic photosynthesis evolves",
      "kind": "moment",
      "tMin": 2430000000.0,
      "tMax": 3400000000.0,
      "t": 2700000000.0,
      "tags": [
        "life",
        "earth-climate"
      ],
      "importance": 0.55,
      "description": "Cyanobacteria evolve oxygen-releasing (oxygenic) photosynthesis, the innovation that eventually oxygenates the atmosphere. It must predate the Great Oxidation Event (onset ~2.46-2.43 Ga), and most estimates put cyanobacteria at 2.7 Ga or earlier. Claims pushing the origin to ~3.4-3.0 Ga rest on disputed biomarkers and stromatolite evidence, so the upper bound is contested.\n",
      "citation": "Lyons, T.W., Reinhard, C.T. & Planavsky, N.J. (2014). \"The rise of oxygen in Earth's early ocean and atmosphere.\" Nature, 506, 307-315. Gumsley, A.P. et al. (2017). \"Timing and tempo of the Great Oxidation Event.\" PNAS, 114(8), 1811-1816.\n"
    },
    {
      "id": "first-life",
      "label": "Earliest evidence of life",
      "kind": "moment",
      "tMin": 3400000000.0,
      "tMax": 4100000000.0,
      "t": 3450000000.0,
      "tags": [
        "life"
      ],
      "importance": 1.0,
      "description": "The oldest markers of biological activity on Earth. Contested and wide: robust stromatolite and microfossil evidence is secure at ~3.4-3.5 Ga (Pilbara, Australia), while claims of biogenic carbon in 4.1 Ga zircons and in 3.7-3.8 Ga Isua (Greenland) metasediments remain disputed and lack scientific consensus.\n",
      "citation": "Allwood, A.C. et al. (2006). \"Stromatolite reef from the Early Archaean era of Australia.\" Nature, 441, 714-718 (~3.43 Ga, robust). Bell, E.A. et al. (2015). \"Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon.\" PNAS, 112(47), 14518-14521 (contested upper bound).\n"
    },
    {
      "id": "moon-forming-impact",
      "label": "Moon-forming impact",
      "kind": "moment",
      "tMin": 4350000000.0,
      "tMax": 4520000000.0,
      "t": 4515000000.0,
      "tags": [
        "earth-climate",
        "catastrophe"
      ],
      "importance": 0.9,
      "description": "A Mars-sized protoplanet collides with the young Earth; debris from the collision accretes into the Moon. Contested: Hf-W and zircon U-Pb dating place the event at 4.51-4.52 Ga, but a 2024 tidal-remelting model argues most lunar rock ages instead record a later heating event around 4.35 Ga rather than the original crystallisation age, so the two camps disagree on which age the rock record actually preserves.\n",
      "citation": "Barboni, M. et al. (2017). \"Early formation of the Moon 4.51 billion years ago.\" Science Advances, 3, e1602365. Contested by: Nimmo, F., Kleine, T. & Morbidelli, A. (2024). \"Tidally driven remelting around 4.35 billion years ago indicates the Moon is old.\" Nature, 636, 598-602.\n",
      "effect": {
        "kind": "giant-impact",
        "windows": [
          {
            "tMin": 4350000000.0,
            "tMax": 4520000000.0
          }
        ]
      }
    },
    {
      "id": "earth-formation",
      "label": "Earth forms",
      "kind": "moment",
      "tMin": 4490000000.0,
      "tMax": 4590000000.0,
      "t": 4540000000.0,
      "tags": [
        "earth-climate"
      ],
      "importance": 1.0,
      "description": "Earth accretes from the solar nebula and differentiates into a metallic core and silicate mantle. Radiometric ages of the oldest meteorites and terrestrial/lunar samples converge on 4.54 +/- 0.05 Ga for the completion of accretion.\n",
      "citation": "Dalrymple, G.B. (2001). \"The age of the Earth in the twentieth century: a problem (mostly) solved.\" Geological Society, London, Special Publications, 190, 205-221.\n"
    }
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      "file": "audio/wind-bbed7193e4.mp3",
      "title": "Desert Sand - Dune Atmosphere",
      "author": "Vrymaa",
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      "title": "Ocean Surf Loop (Ribeira Grande)",
      "author": "Nox_Sound",
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      "title": "Volcano Mount Yasur, Tanna Island (excerpt)",
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      "title": "Goats Moving and Bleating in a Pen",
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      "file": "audio/impact-81a0e5c7ee.mp3",
      "title": "Long Rumble for Earthquake or Explosion",
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  "credits": [
    {
      "sourceId": "astronomy",
      "title": "Earth's Day Length, Lunar Distance, Solar Luminosity and Obliquity",
      "citation": "Gough, D.O. (1981) 'Solar interior structure and luminosity variations', Solar Physics 74, 21-34. Williams, G.E. (2000) 'Geological constraints on the Precambrian history of Earth's rotation and the Moon's orbit', Reviews of Geophysics 38(1), 37-59. Mitchell, R.N. & Kirscher, U. (2023) 'Mid-Proterozoic day length stalled by tidal resonance', Nature Geoscience 16, 567-569. Lantink, M.L., Davies, J.H.F.L., Ovtcharova, M. & Hilgen, F.J. (2022) 'Milankovitch cycles in banded iron formations constrain the Earth-Moon system 2.46 billion years ago', PNAS 119(40), e2117146119. Laskar, J., Robutel, P., Joutel, F., Gastineau, M., Correia, A.C.M. & Levrard, B. (2004) 'A long-term numerical solution for the insolation quantities of the Earth', Astronomy & Astrophysics 428, 261-285. Full per-checkpoint citations in README.md.",
      "licence": "N/A -- no dataset redistributed. Values are computed from published closed-form formulae and cited point measurements; see README.md for the citation attached to every checkpoint.",
      "url": ""
    },
    {
      "sourceId": "audio-stems",
      "title": "CC0 Ambience Stems",
      "citation": "No single dataset. Each stem is an independently CC0/public-domain-licensed audio recording; see stems.toml for per-file author, URL and licence.",
      "licence": "CC0 1.0 / public domain only -- every individual file's real licence and source URL is in stems.toml; see README.md",
      "url": "https://github.com/finndersen/earthlapse/blob/main/sources/audio-stems/stems.toml"
    },
    {
      "sourceId": "basemap",
      "title": "Natural Earth II with Shaded Relief, Water, and Drainages (1:10m)",
      "citation": "Natural Earth. Free vector and raster map data @ naturalearthdata.com. Natural Earth II with Shaded Relief, Water, and Drainages, 1:10m raster.",
      "licence": "Public domain (Natural Earth: \"All versions of Natural Earth raster + vector map data found on this website are in the public domain\")",
      "url": "https://naciscdn.org/naturalearth/10m/raster/NE2_LR_LC_SR_W_DR.zip"
    },
    {
      "sourceId": "cities",
      "title": "Historical Urban Population, 3700 BC - AD 2000 (Chandler + Modelski)",
      "citation": "Reba, M., Reitsma, F. & Seto, K.C. Spatializing 6,000 years of global urbanization from 3700 BC to AD 2000. Sci Data 3, 160034 (2016). https://doi.org/10.1038/sdata.2016.34",
      "licence": "CC BY 4.0 (each of the three figshare deposits independently, confirmed via the figshare API)",
      "url": "https://www.nature.com/articles/sdata201634"
    },
    {
      "sourceId": "cliopatria",
      "title": "Cliopatria: historical empires, 3400 BCE - 1900 CE",
      "citation": "Chalstrey, E., Bennett, J. & Mutch, E. (2024). Cliopatria: A geospatial database of world-wide political entities from 3400BCE to 2024CE (v0.0.1) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.13363121. Methods: Bennett, J. et al., \"Cliopatria: a geospatial dataset of world historical polities\", SocArXiv preprint osf.io/24wd6. Seshat Global History Databank: https://seshatdatabank.info/",
      "licence": "CC BY 4.0 (confirmed both via the Zenodo record's own metadata, license.id == \"cc-by-4.0\", and the repository's committed LICENSE.md)",
      "url": "https://zenodo.org/api/records/13363121/files/Seshat-Global-History-Databank/cliopatria-v0.0.1.zip/content"
    },
    {
      "sourceId": "co2-o2",
      "title": "Atmospheric CO2: Mauna Loa, Antarctic ice-core composite and GEOCARB III",
      "citation": "Lan, X. (NOAA GML) and Keeling, R. (Scripps Institution of Oceanography): Mauna Loa annual mean CO2. Bereiter, B. et al., 2015: Revision of the EPICA Dome C CO2 record from 800 to 600 kyr before present, Geophysical Research Letters, doi:10.1002/2014GL061957. Berner, R.A. and Z. Kothavala, 2001: GEOCARB III: A Revised Model of Atmospheric CO2 over Phanerozoic Time, American Journal of Science, v.301, pp.182-204.",
      "licence": "US public domain (NOAA NCEI Paleoclimatology) and NOAA GML data, freely available with credit; per-file detail in [[artefacts]]",
      "url": "https://github.com/finndersen/earthlapse/blob/main/sources/co2-o2/README.md"
    },
    {
      "sourceId": "events-core",
      "title": "Curated Earth History Events",
      "citation": "Every event in data/events.yaml carries its own specific citation. This manifest's citation covers only the ICS International Chronostratigraphic Chart v2024/12, stratigraphy.org, used as a boundary-dating reference.",
      "licence": "CC0 (Wikidata candidate pool, unused here) + ICS chart free-for-research/non-commercial-use-with-attribution (not modified beyond resizing) + per-event literature citations retain their own copyright, paraphrased not copied — see README.md",
      "url": ""
    },
    {
      "sourceId": "globe-regimes",
      "title": "Pre-1 Ga Globe Regimes",
      "citation": "Every regime in data/globe_regimes.yaml carries its own specific citation. See README.md for the full source list.",
      "licence": "N/A -- no dataset redistributed. Every regime is a literature-cited interval, hand-curated directly into data/globe_regimes.yaml; see README.md for the full citation list.",
      "url": ""
    },
    {
      "sourceId": "hyde",
      "title": "HYDE 3.2.1 cleared land and population density: cropland, pasture, converted rangeland, rangeland and population count, 10,000 BCE - 2015 CE",
      "citation": "Klein Goldewijk, K., A. Beusen, J. Doelman and E. Stehfest (2017). Anthropogenic land-use estimates for the Holocene; HYDE 3.2. Earth System Science Data 9, 927-953. https://doi.org/10.5194/essd-9-927-2017. Data: Klein Goldewijk, C.G.M. (2017). Anthropogenic land-use estimates for the Holocene; HYDE 3.2 [dataset]. DANS. https://doi.org/10.17026/DANS-25G-GEZ3",
      "licence": "CC0-1.0 (DANS deposit doi:10.17026/DANS-25G-GEZ3). The dataset's own bundled readme separately states CC BY 3.0 for the data; both are permissive, and the citation field of this manifest is given regardless of which applies. HYDE 3.3 is CC BY-NC-SA 4.0 and is explicitly NOT used.",
      "url": "https://archaeology.datastations.nl/api/access/datafile/5490328"
    },
    {
      "sourceId": "lineage",
      "title": "The Ancestor Lineage: LUCA to Homo sapiens",
      "citation": "Every node in data/lineage.yaml carries its own specific citation. Principal syntheses used across multiple adjacent nodes: Betts, H.C. et al. (2018) Nature Ecology & Evolution 2, 1556-1562 (early life); dos Reis, M. et al. (2015) Current Biology 25(22), 2939-2950 (animal origins); dos Reis, M. et al. (2012) Proc. R. Soc. B 279(1742), 3491-3500 (placental mammal timescale); Chatterjee, H.J. et al. (2009) BMC Evolutionary Biology 9, 259 (primate divergence times).",
      "licence": "CC BY 4.0 (this compilation); dates are facts cited from the listed publications",
      "url": ""
    },
    {
      "sourceId": "lr04",
      "title": "LR04 global Pliocene-Pleistocene benthic d18O stack",
      "citation": "Lisiecki, L.E. and M.E. Raymo, 2005: A Pliocene-Pleistocene stack of 57 globally distributed benthic d18O records. Paleoceanography 20, PA1003, doi:10.1029/2004PA001071. Data: NOAA NCEI Paleoclimatology, doi:10.25921/k88j-0106. Sea-level scaling anchored to Lambeck, K. et al., 2014: Sea level and global ice volumes from the Last Glacial Maximum to the Holocene. PNAS 111(43), 15296-15303, doi:10.1073/pnas.1411762111.",
      "licence": "CC-BY-3.0 (identical values on PANGAEA, doi:10.1594/PANGAEA.701576); NOAA NCEI distributes its copy without restriction, citation requested",
      "url": "https://www.ncei.noaa.gov/pub/data/paleo/contributions_by_author/lisiecki2005/lisiecki2005-d18o-stack-noaa.txt"
    },
    {
      "sourceId": "paleodem",
      "title": "PALEOMAP PaleoDEMs (Scotese & Wright 2018) -- 1-degree, 0-540 Ma",
      "citation": "Scotese, C.R. and Wright, N.M. (2018). PALEOMAP Paleodigital Elevation Models (PaleoDEMs) for the Phanerozoic. PALEOMAP Project. Dataset, Zenodo. https://doi.org/10.5281/zenodo.5460860",
      "licence": "CC BY 4.0",
      "url": "https://zenodo.org/api/records/5460860/files/Scotese_Wright_2018_Maps_1-88_1degX1deg_PaleoDEMS_nc.zip/content"
    },
    {
      "sourceId": "plates-neoproterozoic",
      "title": "Merdith et al. 2021 continental polygons (1000-540 Ma), stylised relief",
      "citation": "Merdith, A.S., Collins, A.S., Williams, S.E., Pisarevsky, S., Foden, J.D., Archibald, D.B., Blades, M.L., Alessio, B.L., Armistead, S., Plavsa, D., Clark, C. and Muller, R.D. (2021). Extending full-plate tectonic models into deep time: Linking the Neoproterozoic and the Phanerozoic. Earth-Science Reviews 214, 103477. doi:10.1016/j.earscirev.2020.103477. Model: Zenodo 4485738 (CC-BY-4.0).",
      "licence": "CC BY 4.0",
      "url": "https://zenodo.org/api/records/4485738/files/SM2_4485738_V2.zip/content"
    }
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}