What is the largest desert in the world?
Antarctica is the largest desert, at about 14 million square km. Deserts are defined by low precipitation, not heat. The Sahara is the largest hot desert.
Scientists call a region a desert when it gets very little precipitation, usually less than about 250 millimeters a year. Large parts of Antarctica get far less than that, mostly as light snow. The cold, dry air holds very little moisture, so the continent is technically a polar desert even though it is covered in ice.
The Arctic is the second-largest desert by the same definition. The Sahara in North Africa, at about 9 million square kilometers, is the largest hot desert and is roughly the size of the United States.
Not all deserts are sandy
Only a small part of the Sahara is covered by sand dunes; much of it is rock and gravel. Other famous deserts include the Arabian Desert, the Gobi in Mongolia and China, which has freezing winters, and the Atacama in Chile, one of the driest places on Earth. Some parts of the Atacama have gone years without measurable rain.
Did You Know?
Antarctica holds about 70 percent of the world's fresh water, locked up as ice, yet it gets so little snowfall that its interior is drier than parts of the Sahara. The McMurdo Dry Valleys have had almost no rain or snow for a very long time.