The Soviet Union, officially the Union of Soviet Socialist Republics, was a socialist federation in Eurasia that existed from 1922 to 1991. Nominally a union of multiple national Soviet republics, its government and economy were highly centralized. 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. The Russian nation had constitutionally equal status among the many nations of the union, but exerted de facto dominance in various respects. Other major urban centres were Leningrad, Kiev, Minsk, Alma-Ata and Novosibirsk.