What is the moscow river that goes to the Caspian sea?

The Moscow River is a major waterway in Russia that flows through the city of Moscow before eventually joining the Oka River, which then connects to the Volga River. The Volga is the longest river in Europe and flows into the Caspian Sea. Thus, while the Moscow River itself does not flow directly to the Caspian Sea, it is part of a river system that leads to it via the Oka and Volga rivers.