The Union of Soviet Socialist Republics (Soviet Union, Union of SSR, abbreviated USSR) is a state in Eurasia that existed from December 30, 1922 to December 26, 1991.The government of the USSR was formed by the supreme bodies of state power of the country - the Central Executive Committee of the USSR (from 1923 to 1938), the Supreme Soviet of the USSR (from 1938 to 1991) - and was accountable directly to these bodies, as well as to the President of the USSR (in 1990-1991) .