The Union of Soviet Socialist Republics (USSR) was a constitutionally socialist state that existed in Eurasia from 1922 to 1991.
The USSR was composed of 15 republics: Armenian, Azerbaijan, Byelorussian, Estonian, Georgian, Kazakh, Kirghiz, Latvian, Lithuanian, Moldavian, Russian Federation, Tajik, Turkmen, Ukrainian and Uzbek.
