[custom_adv] The Soviet Union, officially the Union of Soviet Socialist Republics , was a socialist state in Eurasia that existed from 1922 to 1991. Nominally a union of multiple national Soviet republics, its government and economy were highly centralized. A girl enjoying the sun at the Kapchagay Reservoir in Kazakhstan. [custom_adv] The country was a one-party state, governed by the Communist Party with Moscow as its capital in its largest republic, the Russian Soviet Federative Socialist Republic. A tourist music festival, 1976. [custom_adv] The Russian nation had constitutionally equal status among the many nations of the union but exerted de facto dominance in various respects. Green Woods recreation and retreat center outside Zvenigorod, 1985. [custom_adv] Other major urban centres were Leningrad, Kiev, Minsk, Alma-Ata and Novosibirsk. The Soviet Union was one of the five recognized nuclear weapons states and possessed the largest stockpile of weapons of mass destruction. Folk choir singing at a country club. [custom_adv] It was a founding permanent member of the United Nations Security Council, as well as a member of the Organization for Security and Co-operation in Europe (OSCE) and the leading member of the Council for Mutual Economic Assistance (CMEA) and the Warsaw Pact. Spring in Moscow, 1959. [custom_adv] The Soviet Union had its roots in the October Revolution of 1917, when the Bolsheviks, led by Vladimir Lenin, overthrew the Russian Provisional Government which had replaced Tsar Nicholas II during World War I. Quality family time, watching a movie, 1974. [custom_adv] In 1922, the Soviet Union was formed with the unification of the Russian, Transcaucasian, Ukrainian and Byelorussian republics. Kids ice-skating in duck formation, 1976. [custom_adv] Following Lenin's death in 1924 and a brief power struggle, Joseph Stalin came to power in the mid-1920s. Socializing at a Moscow cafe, 1961. [custom_adv] Stalin committed the state's ideology to Marxism–Leninism (which he created) and initiated a centrally planned economy which led to a period of rapid industrialization and collectivization. Students during winter break at the Abramtsevo resort, 1961. [custom_adv] During this period of totalitarian rule, political paranoia fermented; the late-1930s Great Purge removed Stalin's opponents within and outside of the party via arbitrary arrests and persecutions of many people, resulting in an estimated 600,000 deaths. Spanish dancer Maria Rosa during her Moscow performance, 1967. [custom_adv] Suppression of political critics, forced labor and famines were carried out by Stalin's government; in 1933, a major famine struck Soviet Ukraine, causing the deaths of some 3 to 7 million people. Moscow hipsters twist on the street, 1980. [custom_adv] Shortly before World War II, Stalin signed the Molotov–Ribbentrop Pact agreeing to non-aggression with Nazi Germany, after which the two countries invaded Poland in September 1939. Almaty integrated home-building factory workers at a concert. [custom_adv] A number of organizations in Russian history were called "council". For example, in the Russian Empire, the State Council, which functioned from 1810 to 1917, was referred to as a Council of Ministers after the revolt of 1905. At the Dzerzhinsky park in Ostankino, Moscow, 1961.