And then one night in 1961, the island was surrounded by the Wall, barbed wire and armed security.

For 28 years, it was the most infamous political barrier in the world - until 9 November 1989, when thousands of East Germans breached the Wall.

Lieutenant Harold Yeager, an East German guard on duty at the Wall that day, said: "It was my decision to begin to allow East German citizens to cross the border, [but] initially I refused to make that decision.

"I was used to reacting in a disciplined fashion to the instructions that came from the party leadership and trusted that they would give the order ... to let people pass.

Lieutenant Harold Yeager: "It was my decision"

"When that order didn't come and when the situation threatened to get out of control, I said 'stop checking these people, open the gates'."

Older Berliners still remember waking up in 1961 to find that West Berlin had been sealed off overnight.

Inga Deutscom said: "It was dreadful to see how the people were standing there, waving to the other side, to their loved ones. You saw them crying and you saw the hankies. It was so painful."

History making amends

The anniversary of the wall's collapse coincides with Kristallnacht, the night in 1938 that Nazi power was turned against the Jews.

Daniel Baremboim, the musical director of the State Opera, found himself compelled to go to the Wall in 1989.

Daniel Baremboim: "So much hope and positive feelings"

He said: "The day is wrought with so many meanings. [There was] the terrible 9 November 1938 with the Kristallnacht - one of the worst atrocities against the Jewish people and against humanity and against culture.

"It is as if history was trying to make amends by also finding 9 November as the day where so much hope and positive feelings were supposed to come."

Ennes Reich, one of the leaders of East Germany's peaceful revolution, is pleased the two parts of the city are united.

He said: "I think it is good that the century closed by finishing that quite unnatural separation of the two Germanys that the Cold War brought us.

"The difficulties notwithstanding we should look forward rather than back."

Mental barriers

But some Berliners still have the mental divide, despite the end of the physical barrier.

One East Berliner told the BBC: "The state of mind of most people didn't change. I don't know anybody from West Berlin and I just go to places in East Berlin. Most people I know do the same."

A West Berliner in the same bar said: "I still refer to myself as a West Berliner. It is still there, the distinctiveness, and there is still a border. That hasn't diminished over the last 10 years."

Briton Nicholas Jackson: "The yesterday, today and tomorrow town"

Nicholas Jackson, a young English archaeologist in Berlin, says that the digging equipment in front of the Reichstag now symbolises the city.

He said: "This site is not just the bare strip for the Berlin Wall.