Today, Germany marks the fall of the Berlin wall 20 years ago, bringing an end to 40 years of communism in East Germany.

Many world leaders have gathered in Berlin. The then leader of the former Soviet Union Mikhail Gorbachev, incumbent Russian Presdient Dmitry Medvedev, and former Solidarity Union leader and Polish president Lech Walensa are among the guests.

US Secretary of State Hillary Clinton said in a speech on Sunday that the events of 9 November 1989 changed the landscape of the whole continent. Her German counterpart Guido Westerwelle said the wall didn't fall but was pushed over by the people.

On Sunday, Chancellor Merkel called the fall of the wall the happiest day in recent German history. She opened a museum on the history of the Glienicker Bridge, where spies were exchanged by the East and the West during the Cold War.

A thousand huge domino stones will be knocked over to symbolise the falling of the wall. The State Opera orchestra and choir will hold a concert at the Brandenburg Gate followed by fireworks and performances by German DJ Paul van Dyk and US band Bon Jovi. 10,000 people are expected to attend the celebrations.

The building of the 155 kilometre wall began on 13 August 1961 to halt the stream of people leaving East Berlin. Around 100 people were shot dead trying to escape to the West once the wall was built.

Photo: Fall of the Berlin Wall 1989 - EPA