The Soviet Union was founded in 1917 after the Russian peasantry overthrew the monarchy. It was ruled as a single-party communist state led by Vladimir Lenin and later Josef Stalin. Stalin's rule was brutal, killing over 60 million people through labor camps and policies. The Soviet Union played a major role in World War 2 as an ally against Germany but the war led to the rise of the Iron Curtain dividing Europe between Western and Soviet spheres of influence. The Soviet Union competed with the US in the Space Race but internal and economic problems led to its collapse in 1991.