The Soviet Union dissolved into 15 countries in a single afternoon

On December 25, 1991, Mikhail Gorbachev resigned as president of the USSR and handed over the nuclear launch codes; the Soviet flag over the Kremlin was lowered for the last time that evening. Fifteen new independent states emerged from a superpower that, weeks earlier, still controlled roughly a sixth of the Earth's land surface.

— Wikipedia contributors, Dissolution of the Soviet Union — December 26, 1991