The seeds for the Cold War are planted during World War I and the ensuing revolution in Russia. In 1917, the new communist government led by Vladimir Lenin withdraws Russia from the war -- and signs a separate peace with Germany. Many of the Western Allies view the new Russian government with suspicion.

Russia's treaty with Germany ends fighting on the Eastern Front. But from 1918 to 1920, civil war rages in Russia -- with the anti-communist forces receiving support from the West and elsewhere as part of an unsuccessful attempt to oust the Bolsheviks.

Following Lenin's death in 1924, Joseph Stalin rapidly rises to power. By the 1930s, Stalin's "Great Purge" is under way. Millions are arrested, and many are executed or sent to prison camps, as Stalin tightens his grip on the nation.
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