The Sahara Desert

The Sahara  Desert is the largest hot desert in the world.  It is the third-largest desert behind the cold deserts of Antarctica and the Arctic.  The Sahara is the worst environment on earth.  It covers 3.6 million square miles (9.4 million square kilometers) and is about one-third the size of the United States (including Alaska and Hawaii) of the African continent.  The name of the desert comes from the Arabic word “desert”.
The Sahara is bordered by the Atlantic Ocean to the west, the Red Sea to the east, the Mediterranean Sea to the north, and the Rice Savannah to the south.  This vast desert spans 11 lands.  These are Algeria, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Western Sahara, Sudan, and Tunisia.
The Sahara Desert has many different topographical features but is most famous for the sand dune fields that are often depicted in the movies.  The peaks can reach up to 600 feet (183 m), but they cover about 15 percent of the total desert.  In addition to the topography here, other topography includes mountains, plateaus, sand and gravel plains, salt flats, basins, and depressions. Mount Kausi, an extinct volcano in Chad, has the highest elevation at 11,204 feet (3,415 m) in the Sahara, and the deepest point on the Saraha at 436 ft (133 m) below sea level in Qatar.
Although water is scarce throughout the region, it contains two permanent rivers (the Nile and the Niger), at least 20 seasonal lakes, and large aquifers, more than 90 of which are the primary source of water in the main desert of the Sahara.  Water management authorities once feared that aquifers in the Sahara would soon dry up due to overuse, but a study published in the journal Geophysical Research in 2013 revealed that “fossil” (irreversible) aquifers were still raining and flowing.