The Russian Revolution began in February 1917 when widespread unrest caused Czar Nicholas II to abdicate. A provisional government was established but faced growing opposition. In October 1917, the Bolsheviks, led by Lenin, seized power in the October Revolution. They established a communist one-party state and fought a civil war against anti-Bolshevik forces from 1918 to 1920. Under Stalin's rule in the 1920s-1930s, the Soviet Union underwent rapid industrialization and the forced collectivization of agriculture, which caused significant hardship and famine.