Lake Baikal is the world’s deepest known lake, reaching about 1,642 meters.
Baikal lies in southern Siberia, Russia, within an ancient rift zone where the Earth’s crust is pulling apart. It is also the world’s oldest existing freshwater lake, commonly estimated at about 25 million years old. The lake holds roughly 20 percent of the planet’s unfrozen surface freshwater, despite covering a much smaller area than many famous lakes.
Baikal is celebrated for its exceptional biodiversity. More than half of its native animal species are endemic, including the Baikal seal, the only seal species living exclusively in freshwater. The lake is about 636 kilometers long and contains 27 islands, with Olkhon the largest. Its extreme depth, great age, and tectonic setting distinguish it from Lake Tanganyika, which is also exceptionally deep but reaches about 1,470 meters.