Giant dominoes symbolising the Berlin Wall are knocked down and fireworks light the Brandenburg Gate in Berlin marking 20 years since the wall toppled. Photo / AP Expand

Giant dominoes symbolising the Berlin Wall are knocked down and fireworks light the Brandenburg Gate in Berlin marking 20 years since the wall toppled. Photo / AP

The key countries in the Cold War pledged yesterday to fight division and meet the new challenges of the 21st century as Europe marked the 20th anniversary of the fall of the Berlin Wall

In emotional addresses delivered at Berlin's Brandenburg Gate, the leaders of the United States, Russia and Britain joined German Chancellor Angela Merkel, Mikhail Gorbachev, Lech Walesa and envoys from across the 27-nation European Union in saluting the event that changed history.

A crowd of more than 100,000 came to the "Festival of Freedom", featuring concerts by the city's classical orchestra and Bon Jovi and saw the toppling of a thousand giant dominoes symbolising the end of Berlin's 28-year division.

Walesa, the Nobel Prize-winning Polish trade unionist who in the early 1980s delivered the first crushing blows against the Iron Curtain, had the honour of pushing over the first of the styrofoam dominoes.

As the last one fell, the crowd chanted "F - R - E - I - H - E - I - T", the letters for "freedom", and the fireworks began to soar.

"Twenty years ago the door to freedom opened up and a seemingly invincible wall that divided a people and an entire continent suddenly became permeable," declared Merkel.

"Our good fortune obliges us to take on the challenges of our time ... freedom and security in the world, the strengthening of growth, wellbeing and justice, the protection of the environment and our natural resources, and the defence of human rights all over the world."

US President Barack Obama, in a surprise video message, said November 9, 1989, would always be a cherished date in the United States. "This anniversary is a reminder that human destiny will be what we make of it. Even in the face of tyranny, people insisted that the world could change."

US Secretary of State Hillary Clinton said: "A physical wall, may have come down but there are other walls that exist that we have to overcome."

French President Nicolas Sarkozy described the fall of the wall as "a call to fight oppression and to tear down all the walls that still separate the world, that divide cities, regions and nations".

"This is the message that a unified Europe proudly embodies and delivers to the world," he said.

British Prime Minister Gordon Brown said the destruction of the seemingly impregnable wall, leading to Europe's reunification, demonstrated the power of will.