The Soviet Union existed from 1922 to 1991; after its break up it was divided into 15 states. Russia, 3 baltic states (Estonia, Latvia, Lithuania), 3 European states (Belarus, Moldova, Ukraine), 5 Central Asian states (Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan) and 3 Caucasus States (Armenia, Azerbaijan, Georgia)
The Russian constitution grants autonomy over local government affairs to around 2 dozen of the most numerous ethnicities. Local government units with a large ethnic population are allowed to designate the ethnic language as an official language in addition to Russia.
One major conflict in the current world is over the Crimea region in Ukraine. Ukraine's minority Russian population started an uprising in the eastern region of Ukraine, where they were clustered (it also possesses coal deposits, a steel industry etc). The Russian government intervened and invaded and seized Crimea claiming that the Russian ethnic minority was endangered. Russia annexed Crimea in 2014, but most countries in the world recognize Ukraine's sovereignty over Crimea.