Nine of them, counted down by area — and the biggest desert on the planet has almost no sand in it at all.
About 492,000 sq km of sagebrush between the Sierra Nevada and the Rockies. Whatever rain falls here stays here — no river in the basin reaches the sea.
Roughly 500,000 sq km of stone and gravel across Syria, Iraq and Jordan. Caravan cities such as Palmyra grew wealthy guiding traders through it.
Argentina's cold desert covers some 673,000 sq km. The Andes wring the rain out of Pacific storms, leaving a windswept steppe grazed by guanacos.
900,000 sq km of red sand across Botswana, Namibia and South Africa. Summer rain lets it carry grass and trees that most deserts cannot support.
1.3 million sq km across Mongolia and northern China. It is mostly bare rock rather than dunes, and cold enough that frost forms on the sand in winter.
2.3 million sq km covering most of the peninsula. At its heart lies the Rub' al Khali, the largest continuous body of sand anywhere on Earth.
9.2 million sq km, the largest hot desert and roughly the size of the United States. Only about a quarter of it is dunes; the rest is rock and gravel.
Around 13.9 million sq km of ice, tundra and frozen sea. Parts of it receive less precipitation in a year than parts of the Sahara do.
14.2 million sq km — the largest desert on Earth. Its McMurdo Dry Valleys are thought to have gone without rain for around two million years.
A desert is defined by what falls from the sky — under 250 mm a year — and never by heat. That single rule is why the two biggest are frozen.