The Volga is the longest river in Europe and the national river of Russia. Flowing 3,530 kilometers through Central Russia, it empties into the Caspian Sea. The river basin covers nearly one-third of European Russia and contains many of the country's largest cities, including Moscow (via the Moscow Canal). The Volga is vital for Russian industry and transport, and it has been heavily dammed to create some of the world's largest reservoirs for hydroelectric power. Historically, it was the highway for the expansion of the Russian state. The river is also home to the Volga sturgeon, though dams have impacted their traditional spawning routes. Its delta on the Caspian Sea is a vast wetland, the largest in Europe, supporting diverse bird and plant species.