Berlin Wall and to pass it on to the coming generations as a reminder to stand up for freedom and democracy to ensure that such injustice may never happen again," entreated Mayor Wowereit. "It has been shown once again: Freedom is invincible at the end. No wall can permanently withstand the desire for freedom", proclaimed President Wulff." Notes Bibliography Further reading Berlin Wall 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 (by
Berlin Wall that year (). Similar, very limited arrangements were made in 1964, 1965 and 1966. In 1971, with the Four Power Agreement on Berlin, agreements were reached that allowed West Berliners to apply for visas to enter East Berlin and East Germany regularly, comparable to the regulations already in force for West Germans. However, East German authorities could still refuse entry permits. East Berliners and East Germans could not, at first, travel to West Berlin or West Germany at all. This regulation remained in force essentially until the fall of the Wall, but over the years several exceptions to these rules