Where is the largest hot desert in the world?

The Sahara Desert in North Africa is the largest hot desert in the world, covering about 9.2 million square kilometres — roughly the size of the United States or China. It stretches across 11 countries and is still growing at its edges through a process called desertification. Although Antarctica and the Arctic are technically larger deserts because a desert is defined by low precipitation rather than heat, the Sahara is the largest of the hot deserts. Temperatures can exceed 50 degrees Celsius by day yet plunge near freezing at night because dry desert air holds little heat. Contrary to popular belief, only about a quarter of the Sahara is sand dunes.