Lake Tanganyika is shared between Tanzania, the Democratic Republic of the Congo (DRC), Burundi, and Zambia. It is situated within the mountainous walls of the valley and is confined by them.

The lake is an African Great Lake located within the Albertine Rift, the western branch of the East African Rift. It is the second-oldest freshwater lake in the world, the second-largest by volume, and the second-deepest.

Source: here