World leaders have been speaking in Berlin at special ceremonies to mark the 20th anniversary of the fall of the Berlin Wall, which changed the political face of Europe. After a day of celebrations attended by tens of thousands of people, the leaders met at the Brandenburg Gate in the centre of the city. In a video message from Washington, President Obama said the people of Berlin and Germany had delivered their own rebuke to tyranny and oppression and had struck out for their freedom. “Let us never forget November 9th, 1989, nor the sacrifices that made it possible. Let us sustain the friendship across the Atlantic that must never be broken and together let us keep the light of freedom burning bright for all who live in the darkness of tyranny and believe in the hope for a brighter day. Thank you.” President Medvedev of Russia said the fall of the wall had helped Russia and Germany put their enmity behind them. And Chancellor Angela Merkel, who was brought up in East Germany, said the night the wall came down was the fulfillment of a dream. After the speeches, Berliners toppled a chain of giant dominoes along the path of the wall, which once divided the city.