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December 1991Reputable sourceWell documented

The Dissolution of the Soviet Union

On the timeline · around December 1991 · The Dissolution of the Soviet Union1986198719881989199019911992

What happened

After a failed hardline coup in August 1991 accelerated the Soviet Union's unraveling, the republics declared independence. On 25 December 1991 Gorbachev resigned, the Soviet flag was lowered over the Kremlin, and the USSR formally ceased to exist the next day, leaving Boris Yeltsin's Russia and fourteen other new states.

Why it matters

The collapse of the Soviet Union ended the Cold War and the bipolar world order it had defined for nearly half a century.

Sources