Lake Baikal is in Southern Siberia in Russia, located between Irkutsk Oblast to the northwest and the Buryat Republic to the southeast, near the city of Irkutsk. It is also known as the "Blue Eye of Siberia". It contains more water than all the North American Great Lakes combined.At 1,637 meters (5,371 ft), Lake Baikal is the deepest lake in the world, and the largest freshwater lake in the world by volume.However, Lake Baikal contains less than one third the amount of water as the Caspian Sea which is the largest lake in the world. Like Lake Tanganyika, Lake Baikal was formed in an ancient rift valley and therefore is long and crescent-shaped with a surface area (31,494 km²), less than that of Lake Superior or Lake Victoria. Baikal is home to more than 1,700 species of plants and animals, two thirds of which can be found nowhere else in the world.At more than 25 million years old, it is the oldest lake in the world.

A Russian mini-submarine attempting to set a record for the deepest freshwater dive on July 29, 2008 was originally reported as being successful, but a correction later emerged that reported the MIR I failed to do so, reaching a depth of only 1,580 meters.

Lake Baikal was known as the "North Sea" in historical Chinese texts. It was situated in the then Xiongnu territory and very little was known about the lake until the Trans-Siberian railway was built between 1896 and 1902. The scenic railway loop encircling Lake Baikal required 200 bridges and 33 tunnels. As it was being built, a large hydrogeographical expedition headed by F.K. Drizhenko produced the first detailed atlas of the contours of Baikal's depths. The atlas demonstrated that Lake Baikal has more water than all of North America's Great Lakes combined — 23,600 cubic kilometers (5,662.4 cu mi), about one fifth of the total surface fresh water on the earth. However, in surface area, it is exceeded by the much shallower Great Lakes Superior, Huron and Michigan in North America, as well as by the relatively shallow Lake Victoria in East Africa. Known as the "Galápagos of Russia", its age and isolation have produced some of the world's richest and most unusual freshwater fauna, which is of exceptional value to evolutionary science.

Lake Baikal is in a rift valley created by the Baikal Rift Zone, where the crust of the earth is pulling apart. At 636 kilometers (395 mi) long and 79 kilometers (49 mi) wide, Lake Baikal has the largest surface area of any freshwater lake in Asia (31,494 km²) and is the deepest lake in the world (1,637 m). The bottom of the lake is 1,371 metres below sea level, but below this lies some 7 kilometers (4.3 mi) of sediment, placing the rift floor some 8–9 kilometers (more than 5 miles) below the surface: the deepest continental rift on Earth. In geological terms, the rift is young and active—it widens about two centimeters per year.

credited to wikipedia and flickr: bobrojulia, adrianclark