What is this page?

Each mark is where a clue comes from. Round dots are clues from people: where something was written down or seen. Squares are clues from nature: where the ice core was drilled or the trees grew. Diamonds are the mysteries. A faint circle means the clue covers a whole region, not one exact spot. A line joins the two clues of a hunch; hover over it to see how far apart they are. Use the buttons to zoom in on part of the world. Things in the sky and things measured all over the world have no place on the map; they are listed under it.

Words we use: Mystery A question nobody has answered yet. Clue from people Something people wrote down or told long ago: a chronicle, a diary, a story, a carving. Clue from nature Something nature recorded by itself: tree rings, ice, rock layers, or the leftovers of an exploded star. Hunch Our guess that a clue from people and a clue from nature are about the same event. Book or paper Where we read it, so anyone can check our work. Step Something we did, in the order we did it.