The Sahara is the largest hot desert on Earth, stretching across much of northern Africa.

The longer version

Dry air sinks over a wide belt near the tropics, and that constant downward motion keeps clouds from forming. With little rain and long hours of direct sun, the ground heats intensely during the day and cools quickly at night. Sand covers only part of the surface; much of it is rock, gravel and dry soil. Strong winds shift dunes slowly across the surface over many years.

Deserts of this kind are defined by low rainfall rather than by heat alone. The Sahara sits under a persistent high pressure zone where storms rarely develop. Plants and animals there survive with deep roots, water stored in tissue, or night time activity. Dust lifted from the region sometimes travels far across the ocean.

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.