Baikal, Lake

Freshwater lake in southern Siberia, Russia, the largest in Asia, and the eighth largest in the world (area 31,500 sq km/12,150 sq mi). Lake Baikal is also the world's deepest lake (up to 1,640 m/5,700 ft) and its oldest, having existed for over 25 million years. It extends for some 636 km/395 mi, and has an average width of 48 km/30 mi. Fed by more than 300 rivers, the main one of which is the Selenga, it is drained only by the Lower Angara. Lake Baikal is famous for its great clarity and the diversity of its fauna.

Lake Baikal freezes over from January to May, except at its outlet into the Angara River. The lake has 1,155 species of animals (including its own breed of seal, the nerpa) and 1,085 species of plants, some 75 % of which are unique to this region. Animals can live at depths of over 1,600 m/5,200 ft in the oxygen-rich water at the bottom of the lake. There are commercial fisheries farming sturgeon and omul(a relative of the salmon). The influx of industrial effluents from the 1960s onwards, chiefly brought down the Selenga River, threatened the lake's ecosystem, but efforts have been made to curb pollution; the lake is being considered for designation as a UNESCO World Heritage Site.

During the Russo-Japanese War 1904–05, a railway line was laid across the frozen surface of Lake Baikal to enable troops to be transported quickly to the Russian Far East.