Lake Kivu is one of the African Great Lakes. Lake Kivu empties into the Ruzizi River, which flows southwards into Lake Tanganyika. The name comes from kivu which means "lake" in Bantu language.
The world's tenth-largest inland island, Idjwi Island, lies in Lake Kivu, as does the tiny island of Tshegera, which also lies within the boundaries of Virunga National Park; while settlements on its shore include Bukavu, Kabare, Kalehe, Sake and Goma in Congo and Gisenyi, Kibuye and Cyangugu in Rwanda.
Lake Kivu is one of three known exploding lakes, along with Cameroonian Lake Nyos and Lake Monoun, that experience violent lake overturns. The trigger for lake overturns in Lake Kivu's case is unknown but volcanic activity is suspected. The gaseous chemical composition of exploding lakes is unique to each lake; in Lake Kivu's case, methane and carbon dioxide due to lake water interaction with a volcano. The amount of methane is estimated to be 65 cubic kilometers). There is also an estimated 256 cubic kilometers of carbon dioxide. The methane is reported to be produced by microbial reduction of the volcanic CO2. The risk from a possible Lake Kivu overturn is catastrophic, dwarfing other documented lake overturns at Lakes Nyos and Monoun, because of the approximately two million people living in the lake basin.