Russia contains Lake Baikal, the world's deepest freshwater lake.
Lake Baikal lies in southern Siberia and reaches a maximum depth of 1,642 metres. It is also the world's oldest existing freshwater lake, with an estimated age of about 25 million years. Its long, narrow basin formed in an active continental rift zone.
Baikal holds approximately 23,615 cubic kilometres of water, about one-fifth of the world's unfrozen surface fresh water. The lake is roughly 636 kilometres long and contains more water than all the North American Great Lakes combined.
Its isolation and age have produced exceptional biodiversity. More than half of its animal species are endemic, including the Baikal seal, the only seal species living exclusively in fresh water. The lake freezes during winter, while its surrounding mountains and forests support a distinctive Siberian ecosystem. Lake Tanganyika is also extremely deep, but Baikal is deeper.