The Cold War officially ended with the fall of:

The Cold War officially ended with the collapse and dissolution of the USSR (Union of Soviet Socialist Republics) in December 1991. The Cold War was a prolonged period of geopolitical tension between the Western bloc, led by the United States, and the Eastern bloc, led by the Soviet Union, lasting roughly from 1947 to 1991.

While several landmark events signalled the winding down of Cold War hostilities - including the fall of the Berlin Wall in November 1989 and the reunification of Germany in 1990 - the Cold War is considered to have officially ended only when the Soviet Union itself ceased to exist on 26 December 1991. With no opposing superpower to sustain the ideological and military rivalry, the bipolar world order that defined the Cold War came to a definitive close.

East Germany's absorption into a unified Germany was a consequence of the broader collapse of communist regimes in Eastern Europe, but it did not by itself end the Cold War. NATO, far from falling, continued to exist and even expanded after 1991. The fall of Berlin (as a divided city) was a powerful symbol, but it was the dissolution of the entire Soviet state that formally concluded the conflict.