The Ural River is a major river in Russia that flows from the Ural Mountains to the Caspian Sea. The Volga River is the longest river in Europe and is also located in Russia, flowing from the Valdai Hills to the Caspian Sea. The Kura River is a major river in the Caucasus region, flowing from Turkey and Georgia to the Caspian Sea. All three rivers, the Ural, Volga, and Kura, are tributaries of the Caspian Sea.