The USSR, or the Union of Soviet Socialist Republics, was a federal socialist state that existed from 1922 to 1991, encompassing much of Eastern Europe and northern Asia. It emerged after the Russian Revolution of 1917 and was characterized by a one-party system led by the Communist Party, significant state control over the economy, and a strong emphasis on military power. The USSR's influence played a critical role in setting the stage for the Cold War and the process of decolonization across various regions.