Sahara Desert, Africa

The Sahara  is the world's hottest desert, and the third largest desert after Antarctica and the Arctic.  At over 9,400,000 square kilometres, it covers most of North Africa, making it almost as large as China or the United States. The Sahara stretches from the Red Sea, including parts of the Mediterranean coasts to the Atlantic Ocean. To the south, it is delimited by the Sahel, a belt of semi-arid tropical savanna that composes the northern region of central and western Sub-Saharan Africa. Some of the sand dunes can reach 180 metres  in height.  The name comes from the plural Arabic language word for desert.  Source