Volga is one of the great rivers of Europe. Rivers of Russia, it is the sixth place, behind in catchment area only the giant Siberian rivers - the Ob, Yenisei, Lena, Amur and Irtysh. It takes its origin in the Valdai Hills where a source take the key, fastening wooden house near the village of Volgin. Mark source 225 m above sea level. Volga flows into the Caspian Sea. The river - 3690 km, basin area km2.Volgu 1,380,000 divided into three parts: the upper Volga - from the source to the mouth of the Oka, Middle Volga - the confluence of the Oka River to the mouth of the Kama and Lower Volga - the confluence of the Kama River to the Caspian Sea. After the construction of the Kuibyshev reservoir boundary between the middle and lower Volga usually considered zhigulevskogo HPP above Samara. During the Civil War of 1918-1920 occurred in the Volga major military action, and it has acquired an important military-strategic importance. Since the late 30's. 20th century Volga began to be used also as a source of hydroelectric power. During the Great Patriotic War of 1941-45, on the Volga was the largest battle of Stalingrad 1942-43.