At the end of World War I in 1918, a republic was proclaimed in Berlin. In 1920, the Greater Berlin Act incorporated dozens of suburban cities, villages, and estates around Berlin into an expanded city. On 30 January 1933, Adolf Hitler and the Nazi Party came to power. Nazi rule destroyed Berlin's Jewish community, which had numbered 170,000 before 1933. After Kristallnacht in 1938, thousands of the city's Jews were imprisoned in the nearby Sachsenhausen concentration camp or, in early 1943, were shipped to death camps, such as Auschwitz. During World War II, large parts of Berlin were destroyed in the 1943–45 air raids and during the Battle of Berlin. Among the hundreds of thousands who died during the Battle for Berlin, an estimated 125,000 were civilians. After the end of the war in Europe in 1945, Berlin received large numbers of refugees from the Eastern provinces. The victorious powers divided the city into four sectors, analogous to the occupation zones into which Germany was divided. The sectors of the Western Allies (the United States, the United Kingdom and France) formed West Berlin, while the Soviet sector formed East Berlin. The Berlin Wall in 1986, painted on the western side. People crossing the so-called "death strip" on the eastern side were at risk of being shot.
The fall of the Berlin Wall in 1989
The founding of the two German states increased Cold War tensions. West Berlin was surrounded by East German territory and East Germany proclaimed East Berlin (described as "Berlin") as its capital, a move that was not recognized by the western powers. As a result of the political and economical tensions brought on by the Cold War, on 13 August 1961, East Germany began building of the Berlin Wall between East and West Berlin and similar barriers around West Berlin, and events escalated to a tank standoff at Checkpoint Charlie on 27 October 1961. West Berlin was now de facto a part of West Germany with a unique legal status, while East Berlin was de facto a part of East Germany. Berlin was completely divided. Although it was possible for Westerners to pass from one to the other (but only through strictly controlled checkpoints) for most Easterners, travel to West Berlin or West Germany was no longer possible. In 1989, with the end of the Cold War and pressure from the East German population, the Berlin Wall fell on 9 November 1989 and was subsequently mostly demolished, with little of its physical structure remaining today. On 3 October 1990, the two parts of Germany were reunified as the Federal Republic of Germany, and Berlin again became the official German capital.