, a mountain range on the border between Uganda and the Democratic Republic of the Congo. Lying just north of the Equator, it extends for about 75 miles (120 km) between Lakes Albert and Edward and is flanked by arms of the Great Rift Valley. Margherita Peak, the 16,763-foot (5,109-m) summit of Mount Stanley, is the highest point in the range and the third highest peak in Africa. The range was first visited by a European explorer, Henry M. Stanley, in 1889, during his last voyage to Africa. It may be the “Mountains of the Moon” mentioned by Ptolemy and thought by ancient scholars to be the source of the Nile River.
Sahara, the vast desert of northern Africa, and the world's largest arid region. It occupies much of the broad northern half of Africa and covers some 3,500,000 square miles (9,000,000 km2), an area only slightly less than that of the United States.