The Berlin Wall was a barrier that divided Berlin from 1961 to 1989. Constructed by the German Democratic Republic (GDR, East Berlin), starting on 13 August 1961, the wall completely cut off (by land) West Berlin from surrounding East Berlin and from East Berlin until it was opened in November 1989. Between 1961 and 1989, the wall prevented almost all such emigration. During this period, around 5,000 people attempted to escape over the wall.
Berlin was jointly governed by the four victorious powers, the city was divided into four sectors, each under the control of a city military commander