Deserts cover roughly a fifth of the Earth's land, and they exist on every continent.

The longer version

A desert is defined by low precipitation, not by heat or sand. Anywhere that loses more water to evaporation than it gains from rain qualifies, which is why cold deserts exist as well as hot ones. Polar regions count on this definition despite being frozen, because so little falls there.

Continentality, mountain barriers and persistent high pressure all create dry zones. Some of the driest areas lie far from the tropics, in the interior of large landmasses or in rain shadows. Vegetation adapts with deep roots, water storage or dormant seeds that wait for rare rain, and surfaces often show a crust of salts.

Where this entry sits

These facts wander across maps, borders, deserts, rivers, mountains, and the extreme corners of the natural world. Each one is short and self-contained, offering a small surprise about places you may never visit rather than anything you actually need. The full list sits on the Geography page, where every entry is listed in order.