World War I
Another revolution happened in Russia in which the Mensheviks lost to the Bolsheviks (these were two rival groups of communists).  The leader of the Bolsheviks was Vladimir Lenin (1870-1924).  The new Bolshevik government asked the Germans for peace and signed the Treaty of Brest-Litovsk with the Central Powers in March 1918 at the city of Brest-Litovsk.  Lenin later died in 1924 and was  replaced by  Joseph Stalin.