The second largest of the lakes of eastern Africa. It is the longest freshwater lake in the world (410 miles (660 km)) and the second deepest (4,710 feet (1,436 m)) after Lake Baikal in Russia. Comparatively narrow, varying in width from 10 to 45 miles (16 to 72 km), it covers about 12,700 square miles (32,900 square km) and forms the boundary between Tanzania and Congo (Kinshasa). It occupies the southern end of the Western Rift Valley, and for most of its length the land rises steeply from its shores.