This is why Germans dislike the 13th of August, 1961!
At midnight on that day, East Germany's police and army began to close the Berlin border over night; this was completed by morning. They also began to build what was later known as the Berlin Wall.
The Berlin Wall (German: Berliner Mauer) was a wall that separated the city of Berlin in Germany from 1961 to 1989. It separated the eastern half from the western half. Many people thought it was a symbol of the Cold War. The Berlin Wall was taken down on November 9, 1989. The Berlin Wall was about 168 km (104 miles) long. It was built to prevent people from escaping from the eastern half of Berlin.
After World War II ended, Germany was divided into four zones, one zone for each of the main Allied countries: France, the United Kingdom, the United States and the Soviet Union. Its capital Berlin was also divided into four zones, so that it was an enclave, like an island inside the Soviet zone. In May 1949, the French, United Kingdom and US zones were made into West Germany (Federal Republic of Germany, Bundesrepublik Deutschland, BRD) and West Berlin. The Soviet zones were made into East Germany and East Berlin. East Germany (German Democratic Republic, Deutsche Demokratische Republik, DDR) was founded on October 7, 1949. Europe, Germany and Berlin were divided by an iron curtain.
The Berlin Wall (German: Berliner Mauer, pronounced [bɛʁˈliːnɐ ˈmaʊ̯ɐ] (listen)) was a guarded concrete barrier that physically and ideologically divided Berlin from 1961 to 1989. Construction of the Wall was commenced by the German Democratic Republic (GDR, East Germany) on 13 August 1961. The Wall cut off (by land) West Berlin from surrounding East Germany, including East Berlin. The barrier included guard towers placed along large concrete walls, accompanied by a wide area (later known as the "death strip") that contained anti-vehicle trenches, "fakir beds" and other defenses. The Eastern Bloc portrayed the Wall as protecting its population from fascist elements conspiring to prevent the "will of the people" in building a socialist state in East Germany.