The Berlin Wall was a guarded concrete barrier that physically and ideologically divided Berlin from 1961 to 1989. Constructed by the German Democratic Republic (GDR, East Germany), starting on 13 August 1961, the Wall cut off West Berlin from virtually all of surrounding East Germany and East Berlin until government officials opened it in November 1989. 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.
The West Berlin city government sometimes referred to it as the "Wall of Shame", a term coined by mayor Willy Brandt in reference to the Wall's restriction on freedom of movement. Along with the separate and much longer Inner German border (IGB), which demarcated the border between East and West Germany, it came to symbolize physically the "Iron Curtain" that separated Western Europe and the Eastern Bloc during the Cold War.
Before the Wall's erection, 3.5 million East Germans circumvented Eastern Bloc emigration restrictions and defected from the GDR, many by crossing over the border from East Berlin into West Berlin; from there they could then travel to West Germany and to other Western European countries. Between 1961 and 1989 the Wall prevented almost all such emigration. During this period over 100,000 people attempted to escape and over 5,000 people succeeded in escaping over the Wall, with an estimated death toll ranging from 136 to more than 200 in and around Berlin.
In 1989 a series of revolutions in nearby Eastern Bloc countries—Poland and Hungary in particular—caused a chain reaction in East Germany that ultimately resulted in the demise of the Wall. The "fall of the Berlin Wall" paved the way for German reunification, which formally took place on 3 October 1990.