The Former Soviet Union, officially known as the Union of Soviet Socialist Republics (USSR), was a federation of multiple republics that existed from 1922 to 1991. It was a major world power during the 20th century, known for its communist government and significant influence in global politics, economics, and culture. The capital was Moscow, and the USSR included countries like Ukraine, Belarus, and the Baltic States. The Soviet Union played a crucial role in World War II and was a key player in the Cold War against the United States. Its collapse in 1991 led to the independence of its republics and significant political and economic changes in the region. The legacy of the USSR continues to impact former member states and global relations today.