Africa contains the Sahara, the world's largest hot desert, which covers roughly 9.2 million square kilometres.
The Sahara stretches across much of North Africa, reaching from the Atlantic Ocean to the Red Sea and from the Mediterranean region toward the Sahel. It includes sand seas, gravel plains, rocky plateaus, mountains, and dry valleys, so it is not simply a continuous field of dunes.
The word Sahara comes from the Arabic ṣaḥrāʾ, meaning “desert.” The region has not always been as dry as it is today: during the African humid periods, grasslands and lakes occupied areas that are now arid. Antarctica is larger than the Sahara and is the world's largest desert overall, but it is a cold desert. The Arabian Desert is another major desert, located in Asia, which is why “largest hot desert” is the precise distinction.