Nyasa, Lake, or, a freshwater lake in the Great Rift Valley of East Africa. Lake Nyasa is bounded on the northeast by Tanzania, on the southeast by Mozambique, and on the south and west by Malawi. Nyasa is Africa's third largest lake, covering an area of 11,200 square miles (28,900 km2). It is 360 miles (580 km) long, 15 to 50 miles (24 to 80 km) wide, and up to 2,280 feet (695 m) deep. Portuguese explorers discovered Lake Nyasa in 1616. It was rediscovered by David Livingstone in 1859.
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.