Addressing the ceremony on Bernauer, a street famously divided by the Wall and now site of a memorial, Mayor Wowereit said the capital was remembering the "saddest day in its recent history".
"It is our common responsibility to keep alive the memories and pass them on to the next generation, to maintain freedom and democracy and to do everything so that such injustices may never happen again," he said.
Earlier, Mr Wulff told Die Welt newspaper that the modern Germany could take pride in "East Germans' irrepressible desire for freedom and West Germans' solidarity with them".
The wall was finally opened in 1989. Link -via Fark
Previously: Read more about the history of the Berlin Wall in The Fall of the Wall.