Cold War: Start of the Berlin Blockade: The Soviet Union makes overland travel between West Germany and West Berlin impossible.

The Cold War was a period of global geopolitical rivalry between the United States (US) and the Soviet Union (USSR) and their respective allies, the capitalist Western Bloc and communist Eastern Bloc, which began in the aftermath of the Second World War and ended with the dissolution of the Soviet Union in 1991. The term cold war is used because there was no direct fighting between the two superpowers, though each supported opposing sides in regional conflicts known as proxy wars. In addition to the struggle for ideological and economic influence and an arms race in both conventional and nuclear weapons, the Cold War was expressed through technological rivalries such as the Space Race, espionage, propaganda campaigns, embargoes, and sports diplomacy.

The Berlin Blockade was one of the first major international crises of the Cold War. During the multinational occupation of post–World War II Germany, the Soviet Union blocked the Western Allies' railway, road, and canal access to the sectors of Berlin under Western control. The Soviets offered to drop the blockade if the Western Allies withdrew the newly introduced Deutsche Mark from West Berlin.

West Berlin was a political enclave which comprised the western part of Berlin from 1948 until 1990, during the Cold War. Although West Berlin lacked any sovereignty and was under military occupation until German reunification in 1990, the territory was claimed by the Federal Republic of Germany, despite being entirely surrounded by the German Democratic Republic. The legality of this claim was contested by the Soviet Union and other Eastern Bloc countries. However, West Berlin de facto aligned itself politically with the FRG from May 1949 and was thereafter treated as a de facto city-state of that country. After 1949, it was directly or indirectly represented in the institutions of the FRG, and most of its residents were citizens of the FRG.