Lake Tanganyika is an African Great Lake. It is the second oldest freshwater lake in the world, second largest by volume, and the second deepest, in all cases after Lake Baikal in Siberia; it is also the world's longest freshwater lake. The lake is divided among four countries – Tanzania, Democratic Republic of the Congo (DRC), Burundi, and Zambia, with Tanzania (46%) and DRC (40%) possessing the majority of the lake. The water flows into the Congo River system and ultimately into the Atlantic Ocean.EtymologyThe name apparently refers to "Tanganika, 'the great lake spreading out like a plain', or 'plain-like lake'."Geography and geological historyLake Tanganyika is situated within the Albertine Rift, the western branch of the East African Rift, and is confined by the mountainous walls of the valley. It is the largest rift lake in Africa and the second largest lake by volume in the world. It is the deepest lake in Africa and holds the greatest volume of fresh water, accounting for 16% of the world's available fresh water. It extends for 676km in a general north-south direction and averages 50km in width. The lake covers 32900km2, with a shoreline of 1828km, a mean depth of 570m and a maximum depth of 1470m (in the northern basin). It holds an estimated 18900km3.