Thirty years ago, June 12, 1987.

General Secretary Gorbachev, if you seek peace, if you seek prosperity for the Soviet Union and Eastern Europe, if you seek liberalization: Come here to this gate! Mr. Gorbachev, open this gate! Mr. Gorbachev, tear down this wall!

…

The totalitarian world finds even symbols of love and of worship an affront. Years ago, before the East Germans began rebuilding their churches, they erected a secular structure: the television tower at Alexander Platz. Virtually ever since, the authorities have been working to correct what they view as the tower’s one major flaw, treating the glass sphere at the top with paints and chemicals of every kind. Yet even today when the sun strikes that sphere–that sphere that towers over all Berlin–the light makes the sign of the cross. There in Berlin, like the city itself, symbols of love, symbols of worship, cannot be suppressed.  [Many Germans call this “Pope’s Revenge”]

Two years later, in November 1989, East Germans issued a decree for the wall to be opened, allowing people to travel freely into West Berlin. In some cases, families that had been separated for decades were finally reunited. The wall was torn down altogether by the end of 1990 upon the collapse of Communism in Eastern Europe and in Soviet Russia itself, marking the end of the Cold War era.

Complete transcript of the speech: http://www.historyplace.com/speeches/reagan-tear-down.htm