The URSS, or Union of Soviet Socialist Republics, was a federal socialist state that existed from 1922 to 1991. It was made up of multiple republics, with Russia being the largest and most influential. The URSS was established after the Russian Revolution and aimed to create a classless society based on Marxist principles. During its existence, the URSS became a major global power, particularly during the Cold War era, competing with the United States for political and military influence. The state was known for its centralized economy and one-party political system, which ultimately faced significant challenges leading to its dissolution in 1991.