Allied intervention in the Russian Civil War

The Allied intervention in the Russian Civil War consisted of a series of multi-national military expeditions that began in 1918. The initial impetus behind the interventions was to secure munitions and supply depots from falling into the German Empire's hands, particularly after the Bolsheviks signed the Treaty of Brest-Litovsk, and to rescue the Allied forces that had become trapped within Russia after the 1917 October Revolution.

Source: Wikipedia — Allied intervention in the Russian Civil War (CC BY-SA 4.0)