N1917, the russian overthrew the tsar and contributed to russia’s exit from the war.

In 1917, the Russian Revolution overthrew the tsar and contributed to Russia's exit from the war.

Explanation:

The Russian Revolution was a large-scale revolution in the Russian Empire that took place in 1917. In a sense, it was a series of revolutions. These resulted in the disappearance of the Tsarist regime and the establishment of the Soviet Union, the first communist state in the world. At the February revolution in 1917 the tsar was deposed and replaced by the Provisional Government. Then, another revolution, the October Revolution, replaced the Provisional Government by a Bolshevik (Communist) government led by Vladimir Lenin. After this a civil war broke out between "Reds" (Bolsheviks / Communists) and "Whites" (Liberals, Mensheviks, Social Revolutionaries and Russian nobility), which lasted from 1917 to 1923. Eventually the Bolsheviks won. In this way, the revolution paved the way for the Union of Soviet Socialist Republics (USSR).