The Volga (Russian: Волга) is a river in central Russia. It is the longest river in Europe, and is also the largest by discharge. It drains into the Caspian Sea. The cities of Nizhny Novgorod, Kazan, Saratov, Samara, Volgograd and Astrakhan are on the river. Moscow is on the Moscow River, which drains into the Oka, flowing into the Volga. The Volga river delta is one of the largest deltas in the world.