What is the Sahara?

The Sahara is the world's largest desert. It stretches across northern Africa from the Atlantic Ocean to the Red Sea. This vast desert covers about 3,500,000 square miles, or more than 30 percent of Africa.

The surface of the Sahara is covered by high, shifting sand dunes called ergs; rocky desert uplands called hamadas; and flat gravel plains called regs. Rock and gravel cover most of the surface. Sand covers only about 10 percent. Much of the desert is a plateau about 2,000 feet above sea level. Peaks in the Ahaggar and Tibesti uplands stand high above the plateau.

The climate of the Sahara is very dry today, with an average rainfall of less than 10 inches a year. Summer temperatures often reach 120 degrees Fahrenheit. Yet rock carvings and paintings have been found that show the region was once fertile. Farmers tilled green fields, and there were herds of elephant and giraffe. The dry beds of rivers and lakes can still be seen. Scientists have also proved the the Saharan region was once down where the South Pole is. It moved to its present location when part of the earth's crust slid northward.

See also : Sahara desert map | Desert animals | Desert features