At over 9,000,000 square kilometers (3,500,000 sq mi), it covers most
of Northern Africa, making it almost as large as the United States or
the continent of Europe. The desert stretches from the Red Sea,
including parts of the Mediterranean coasts, to the outskirts of the
Atlantic Ocean. To the south, it is delimited by the Sahel: a belt of
semi-arid tropical savanna that comprises the northern region of
central and western Sub-Saharan Africa.
The Sahara has an intermittent history that may go back as much as
3 million years.[1] Some of the sand dunes can reach 180 meters
(600 ft) in height.[2] The name comes from the Arabic word for desert "SAHRA"
