USSR: Union of Soviet Socialist Republics
The full form of USSR is Union of Soviet Socialist Republics. It had 15 Soviet Socialist Republics (S.S.R.’s): Armenia, Azerbaijan, Belarus, Estonia, Georgia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, Russia, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan. The capital was Moscow, then and now the capital of Russia.