Barrier surrounding West Berlin that closed off East Germans access to West Berlin from 1961 to 1989 and served as a symbol of the Cold War 's division of East and West Germany.
The barrier was built in response to the flight of about 2.5 million East Germans to West Germany in the years 194961. First erected on the night of Aug. 1213, 1961, it developed into a system of concrete walls topped with barbed wire and guarded with watchtowers, gun emplacements, and mines. It was opened in the 1989 democratization that swept through eastern Europe and has been largely torn down.