The Sahara Desert extends eastward from the Atlantic Ocean some 3,000 miles to the Nile River and the Red Sea, and southward from the Atlas Mountains of Morocco and the Mediterranean shores more than 1,000 miles to the savannah called the Sahel. More than 16 times the size of France, the Sahara Desert blankets nearly all of Mauritania, Western Sahara, Algeria, Libya, Egypt and Niger; the southern half of Tunisia; and the northern parts of Mali, Chad and Sudan. Image credit: NASA's MODIS instrument (Moderate Resolution Imaging Spectroradiometer)