Lake Baikal, in southeastern Siberia, is surely one of the most fascinating places on Earth. Filling the deepest continental rift on the planet, this lake holds 20% of our liquid fresh water, more than all of America's Great Lakes combined. Baikal is 395 miles long, up to 50 miles in width and averages 1 mile in depth. The rift itself is 5 miles deep but the lake's sediment is 4 miles thick; both the rift and the lake are thought to be 25-30 million years old, making Baikal the deepest, largest (by volume) and oldest freshwater lake on Earth. Surrounded by mountains and filled by more than 300 rivers, Lake Baikal drains to the Arctic Ocean via the Lena River.
More impressive than its size, Lake Baikal is home to over 1000 plant species and more than 1200 animal species, 80% of which are endemic to the lake (they are found nowhere else on the planet). Baikal harbors 56 species of fish, including its famous omul salmon, and is home to the only freshwater seal on Earth, the Baikal seal, locally known as the nerpa. It is thought that these seals migrated from the Arctic Ocean during the late Tertiary Period, when the Lena was a much larger river.
The mountains and taiga surrounding the lake are also rich in wildlife, over 80% of which are endemic to the region. These include brown bears, sable, lynx, moose, reindeer, pikas and the Siberian chipmunk; among the unique bird species are white-tailed eagles and grey herons. The only threat to this natural paradise is, of course, human activity. Regional air pollution is a problem and the pristine lake waters are threatened by effluent from a pulp mill, built on the south shore of Baikal.
