Low-key ceremonies have been held in Germany to mark the 15th anniversary of the fall of the Berlin Wall.
The wall came down to scenes of jubilation in 1989
Berlin's Mayor Klaus Wowereit laid a wreath at a preserved section of the wall and a special service was held at a rebuilt chapel on the former border.
"It's a permanent work of remembering. It's important to explain what the wall was," he told the BBC.
The wall was built by the East German communist authorities in 1961, to prevent citizens fleeing to the West.
The wall became the most potent symbol of the Cold War.
The BBC's Ray Furlong, in Berlin, says that 15 years on, memories are dimming of a cold November night when the impossible happened - East Berliners were suddenly free to cross into the West.
Chancellor Gerhard Schroeder on Tuesday paid tribute to the peaceful revolution against the communist regime that culminated in the wall's destruction.
"November 9 is a day marking the triumph of freedom and democracy. The people of East Germany broke down the wall 15 years ago and conquered a cynical dictatorship," he said.
Mayor Wowereit played down the continuing east-west divisions, saying that "15 years after reunification I think we're in a better condition to plan our future in a democratic way, a way of unity".
He noted that a generation of Germans had now grown up in a democratic system, but "for people in their 50s it's not so easy to forget the past".
In 1989, Soviet leader Mikhail Gorbachev was pursuing glasnost (openness). The hardline leadership in East Berlin was powerless to stop the first mass demonstrations in decades.
Opening the wall was a moment of panic that forced the collapse of the communist bloc and led to German reunification.
But it is an uneasy unity, our correspondent says. The former communist east still lags behind the west economically, despite receiving huge subsidies, and the situation is causing simmering resentment in both halves of Germany.