Lake Baikal is the deepest known lake on Earth, reaching about 1,642 metres below its surface.
Located in southern Siberia, Russia, Baikal formed in an active continental rift zone. Its great age—roughly 25 million years—has allowed a distinctive ecosystem to develop, including the endemic Baikal seal, the only seal species living exclusively in fresh water. The lake is also the world’s oldest existing freshwater lake by many scientific estimates.
Baikal contains about 20 percent of the world’s unfrozen surface fresh water, more than any other lake. It is long and narrow, stretching for roughly 636 kilometres. Lake Tanganyika is the second-deepest lake, while Lake Superior is the largest freshwater lake by surface area. These distinctions are often confused because “largest” can mean area, volume, or depth.