Officially the Union of Soviet Socialist Republics (U.S.S.R.), this was a group of communist countries ruled by a government in Moscow. It was created after the 1917 communist revolution in Russia, which overthrew the Czar and out in place a system of soviets (workers councils). The government became very oppressive; Joseph Stalin came to power in the 1920s and had a brutal regime where anybody who didn’t support him was killed or sent to gulags (prison work camps). Millions of people were killed or tortured under the system. There were also major famines and poverty. Despite this, the U.S.S.R. became a world superpower after World War II, gaining a lot of land and influence. It competed with the U.S. during the Cold War and was a major nuclear power. Other leaders took over after Stalin died, but the U.S.S.R. collapsed in 1991, due to economic failures and dissatisfied citizens. Many of the regions declared independence, while Russia still has a tense relationship with America to this day.