In 1945, Adolf Hitler committed suicide and Nazi Germany surrendered to the Allies. The Allies—the United States, the United Kingdom, France, and the Soviet Union—occupied the defeated nation. These four countries were able to agree on some aspects of postwar Germany. For example, they presided over the Nuremberg Trials of Nazi war criminals. They also agreed that much German territory would be annexed by Poland and the Soviet Union.

But they could not agree on a postwar government for Germany. America, Britain, and France wanted a democratic Germany, and Moscow wanted a communist system for the country. The four zones of occupation in Germany and Berlin were supposed to be temporary. However, they became permanent as the two sides began to organize separate governments for their lands. By 1949, West Germany and East Germany were established as separate countries, with capitols in Bonn and East Berlin, respectively.

West Berlin was an isolated capitalist zone within East Germany, and Moscow wanted to add it to East Germany. Road links between West Germany and West Berlin were cut off in 1948, so the West deftly responded with the Berlin Airlift.

There were stark economic differences between West Germany and East Germany. West Germany was helped by the Marshall Plan. East Germany remained relatively poor, and its people became envious of West Germans' prosperity. Dissatisfied East Germans revolted in 1953, but they were put down by Soviet tanks.

Because of the greater prosperity in the West, East Germans increasingly fled to the West in the 1950s. Communist East Germany built the Berlin Wall in 1961 to keep its people from leaving. In 1989, East Germans were allowed to leave again, so the Berlin Wall collapsed. In 1990, Germany became united as a democracy, and Berlin became its capital. By 1991, the Soviet Union had disintegrated, and the Cold War ended.