In 1989, a series of radical political changes occurred in the Eastern Bloc, associated with the liberalization of the Eastern Bloc's authoritarian systems and the erosion of political power in the pro-Soviet governments in nearby Poland and Hungary.
After several weeks of civil unrest, the East German government
announced on 9 November 1989 that all GDR citizens could visit West
Germany and West Berlin. Crowds of East Germans crossed and climbed onto
the wall, joined by West Germans on the other side in a celebratory
atmosphere.
The date on which the Wall fell is considered to have been 9 November
1989, but the Wall in its entirety was not torn down immediately.
Starting that evening and in the days and weeks that followed, people
came to the wall with various tools to chip off souvenirs, demolishing
lengthy parts of it in the process and creating several unofficial
border crossings. Contrary to popular belief the wall's actual demolition did not begin until Summer 1990 and was not completed until 1992.
http://en.wikipedia.org/wiki/Berlin_Wall
http://i.imgur.com/y9P7F.jpg