Lake Baikal or Lake Baikal ( in Russian : о́зеро Байка́л): is a great lake located in southern Siberia in Russia . It is the deepest freshwater lake in the world with a depth of 1642 m and includes the largest volume of freshwater in the world. It is also the oldest lake in the world and it was formed almost 25 million years ago due to the movements of the crust. There are types of wild and marine animals that live in and near the lake. It is 395 miles long and has an average width of 3 miles and infects 336 rivers. It has been listed since UNESCO on the World Heritage List since 1996. It is located in a collapsible groove, and it is similar to that of Tanganyika Lake in Africa, and it contains more than 20% of the fresh water that is not frozen in the world. The large volume of lake water affects the atmosphere of the neighboring regions. Cold in the summer from the distant areas, and the surface of the lake accumulates in the period from January to May. Despite the mouth of 336 rivers in Lake Baikal, there is only one river coming out of it, which is the Anjara River .