Russia participated in World War 1 as part of the Allied forces against Germany. They fought in major battles like Tannenberg, Verdun, and the Somme and suffered over 35 million military and civilian casualties. Public discontent with Russia's involvement in the war grew, allowing the Bolsheviks under Vladimir Lenin to promise to withdraw from the war and take power. This led to Russia signing the Treaty of Brest-Litovsk in 1918 to end its war with Germany.