Lake Baikal is the world’s oldest and deepest lake. It is the second most voluminous lake, after the Caspian Sea. As the most voluminous freshwater lake in the world, with an average depth of 744.4 m, Lake Baikal contains roughly 20% of the world’s surface fresh water, and is located in the south of the Russian region of Siberia. At 1,642 metres Lake Baikal is the deepest, and among the clearest of all lakes in the world. At more than 25 million years old, Baikal is also the world’s oldest lake. Like Lake Tanganyika, Lake Baikal was formed as an ancient rift valley, having the typical long crescent shape with a surface area of 31,722 km2/12,248 sq mi, 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 and was declared a UNESCO World Heritage Site in 1996. It is also home to Buryat tribes who reside on the eastern side of Lake Baikal, rearing goats, camels, cattle and sheep, where the regional temperature varies from a minimum of ?19 °C in winter to maximum of 14 °C in summer.