By: –

World leaders have hailed the Berlin Wall’s fall in celebrations 20 years on from the upheaval that changed Europe.

German Chancellor Angela Merkel was joined at the Brandenburg Gate by Russia’s Dmitry Medvedev, France’s Nicolas Sarkozy and UK PM Gordon Brown.

In a special video address, US President Barack Obama said Berliners had rebuked tyranny on 9 November 1989.

The event two decades ago led Germany to reunify, caused the collapse of the Soviet Union and the Cold War’s end.

Communist East Germany erected the 155-km (96-mile) concrete barrier in 1961 to encircle West Berlin and prevent citizens from fleeing into the capitalist enclave.

At least 136 people are thought to have been killed at the wall while trying to escape.

Ms Merkel – who grew up in East Germany – presided over Monday’s celebrations, which were attended by tens of thousands of people despite a downpour of rain.

She led a procession of leaders through the Brandenburg Gate – the symbol of German reunification in 1990.

The presidents of Russia and France, the British premier and US Secretary of State Hillary Clinton were among those who joined the German chancellor.

Ms Merkel said the events of 20 years ago had shown the world could tackle new challenges, from poverty to climate change.

“Together we brought down the Iron Curtain and I am convinced this can give us the strength for the 21st century,” she said.

Mrs Clinton also spoke, before introducing a surprise video address from Washington by Mr Obama.

“There could be no clearer rebuke of tyranny. There could be no stronger affirmation of freedom,” he said of the wall’s tearing down.

Mr Medvedev said the wall’s collapse had helped Russia and Germany end their World War II enmity.

He said he hoped everyone had rejected the dividing lines represented by the wall.

In his speech, Mr Brown told Berliners: “You dared to dream in the darkness. You knew that while force has the temporary power to dominate, it can never ultimately dictate.”

After the leaders spoke, a chain of 1,000 giant foam dominoes – painted with messages of freedom by young people – was toppled along where the wall once stood.

The symbolic act was to reflect how the then Communist governments of Eastern Europe fell one after another.

The first wave of dominoes were knocked over by former Polish President Lech Walesa and ex-Hungarian Prime Minister Miklos Nemeth.

Mr Nemeth’s decision to open his country’s borders first allowed East Germans to flee to the West.

The festivities were capped with fireworks and a concert featuring music from Berlin’s State Opera and the American rock band Bon Jovi.

Earlier in the day, Ms Merkel retraced her steps on the night the wall fell by crossing the first checkpoint to open 20 years ago.

The German chancellor was joined by ex-Soviet leader Mikhail Gorbachev and Mr Walesa, the former Polish trade union leader and later president, whose movement was the first to challenge Communist rule successfully in Eastern Europe.

There were cheers from hundreds of onlookers as Ms Merkel praised Mr Gorbachev for helping to make change possible.

Earlier, Ms Merkel said in a TV interview that German unity was still incomplete, as the East lagged in economic growth.