Drag to spin the globe, scroll or pinch to zoom, right-drag (or ctrl-drag) to tilt. Zoom all the way in and every river, lake, coastline and mountain shows up. Click a pin to read about the place. The layers button at the top right (hover or tap it) opens the chips that switch layers on and off.
Add the place to the address, and the globe opens there with a pin:
thinkmachine.org/earth/?place=gobekli-tepe thinkmachine.org/earth/?place=fertile-crescent&place=mesoamerica
Known places (more in places.js):
Any spot on Earth works too. Pins are lat,lng,Label; lat/lng/zoom set the view (zoom 1 = whole globe, 6 = a country, 10 = a valley):
thinkmachine.org/earth/?pin=30.03,31.24,Giza&zoom=5 thinkmachine.org/earth/?lat=59,lng=-3&zoom=8
Timeline: add ?year=-9500 (negative = BC) and the page opens with the timeline at that year: the coast for that sea level, the ice, the borders and the sites of the time. The "i" button on the timeline says how accurate each part is.
thinkmachine.org/earth/?year=-9500&place=gobekli-tepe
Add &show=satellite,cities or &hide=countries to pick layers (satellite, relief, rivers, borders, countries, water, peaks, cities).
The slider redraws four things for the year you pick. Each comes from a different kind of evidence, and each is accurate in a different way. Read this before trusting a detail.
During the Ice Age so much water was locked in ice that the sea stood about 125 m lower 20,000 years ago. Britain was joined to Europe, Alaska to Siberia, and Southeast Asia was one landmass. The page redraws the shore by taking today's elevation map (which includes the sea floor) and coloring everything above that year's sea level as land. The sea-level numbers are rounded from a standard reconstruction (Lambeck and colleagues, 2014).
Where it is wrong: the sea floor data is coarse (about 1 km, blurrier offshore), so small islands and narrow straits can be off. Land itself moves: Scandinavia, Scotland and the Hudson Bay region are still rising after the ice left, so their ancient shores sat lower than this map shows, while river deltas (the Nile, the Mississippi) did not exist yet and the Black Sea was a lake until about 7000 BC. Lakes are drawn as they are today. Take the drawn shore as right to within a few kilometers in most places and tens of kilometers near former ice.
The white areas are rough outlines of the ice sheets over North America, northern Europe and Patagonia, hand-drawn from published reconstructions at eight moments between 20,000 BC and 4500 BC. The ice does not move between those moments, and the edge can be 100–200 km off. Mountain glaciers (the Alps, Tibet, the Rockies, Iceland) are left out. Greenland and Antarctica are the base map's own ice, which is today's extent.
Political borders come from a crowd-sourced atlas of 54 world maps between 10,000 BC and 2010 (the historical-basemaps project). The page shows the latest map at or before the year on the slider, so a border can be up to 2,000 years out of date in early times and up to a century in the Middle Ages. Solid lines are borders fixed by treaty; dashed lines are the mapmakers' estimates. Before about 3000 BC the areas are cultures (people who made the same pottery and tools), not states: nobody ruled a line on the ground. Many empires had no fixed edge at all, and the atlas has to pick one. Names are the ones historians use today. Treat every border as a sketch for a classroom, not evidence.
Before 10,000 BC there is no map to show, and modern borders are hidden while a historical map is on.
The dots and circles are a short list written for this page. Each card says how sure its date is: well dated (radiocarbon, tree rings or written records; good to within decades, or to the year in recent times), approximate date (rounded from the literature, usually to the nearest century or two), date debated (specialists disagree, sometimes by a thousand years), or traditional date (a date handed down, not measured). A circle means "somewhere about here", not a measured area.
Radiocarbon dates are given here in calendar years (already corrected), which is why a "9,500 BC" site may be called "11,500 years old" elsewhere. BC years count down: 9500 BC is earlier than 9000 BC.
The land colors, rivers, lakes and relief are today's. The Sahara was grassland between about 9000 and 3500 BC, the Persian Gulf was dry land until about 6000 BC, and rivers have wandered, but the base map cannot show that. The page is a globe with history pinned onto it, not a reconstruction of the past Earth.
Elevation and sea floor: Mapzen Terrain Tiles (SRTM, ETOPO1, GEBCO). Sea level: Lambeck et al., PNAS 2014. Ice: Dalton et al. 2020 (North America), Hughes et al. 2016 (Eurasia), Davies et al. 2020 (Patagonia), simplified by hand. Borders: aourednik/historical-basemaps on GitHub (GPL-3). Sites and events: written for this page from standard references; corrections welcome in earth/history.js.