.... is a phrase that means something quite different to the Facebook generation than it did to my parents' generation. Berlin - BFPO 45, if you had cause to write to British forces stationed there - had a symbolism for that generation that it is difficult to appreciate now.
My parents met in Berlin when both were serving in the British Army, though it is not a city I have visited. I was acutely aware of the significance of the night that the wall "came down", or perhaps more accurately, was "opened".
The BBC are today reporting on the 50th anniversary of the building of the Berlin Wall. They have linked from that page to a page marking the 20th anniversary of the opening of the crossing points, here, in which is embedded Brian Hanrahan's coverage of the night itself.
I have two particularly vivid memories of the night the wall opened. One is the confusion of an East German girl crossing into the West when she was asked if she would go back. Effectively, her response was to say that she just did not know. This was part of Capital Radio's coverage. The second was waking up the next morning and thinking, before I even took my head off the pillow, "the world has changed".