Tanganyika, Lake, second largest lake of Africa, c.12,700 sq mi (32,890 sq km), E central Africa on the borders of Tanzania, Congo (Kinshasa), Zambia, and Burundi. It is c.420 mi (680 km) long and up to 45 mi (72 km) wide. The lake lies in the Great Rift Valley (alt. 2,534 ft/772 m) and is the world's second deepest (c.4,700 ft/1,430 m) freshwater lake. Part of the lake's overflow eventually reaches the Atlantic Ocean by way of the Lukuga River. Lake Tanganyika has important fisheries and there are large populations of hippopotamuses and crocodiles. Steamer service connects the chief lakeside cities. David Livingstone and Henry M. Stanley explored (1871) the region. During World War I there were several small naval engagements between the British and the Germans on the lake.