Russian Revolution (1917)

The 1917 Russian Revolution—actually two revolutions, the February democratic uprising and the October Bolshevik coup—created the world's first communist state, a regime that spanned 11 time zones and influenced communist movements on every continent for 70 years. It is cheaper than the typical rival revolution in human cost for initial success, with fewer than 10,000 casualties during the October seizure of power, compared to the French Revolution (#1), which saw over 40,000 executions in the Reign of Terror alone. The Soviet Union, born from this revolution, deployed 50,000 nuclear warheads at its peak, defining the Cold War and reshaping global order until its collapse in 1991. This revolution's ideological impact remains unmatched, with communist parties still active in over 50 countries, a legacy that outperforms #2 in political durability.