(RFE/RL) -- Former Polish opposition leader and President Lech Walesa set in motion the toppling of a thousand giant dominos in Berlin on November 9 to mark the moment when the wall separating the city between the free West and the communist East was breached 20 years ago.
The ripple of the foam bricks, which spanned a half-mile stretch along where the Berlin Wall once stood, was the culmination of a daylong celebration in Berlin to mark one of the watershed events in the collapse of communism in Eastern Europe 20 years ago.
The end of the Berlin Wall hastened the collapse of the Iron Curtain and, within the year, led to the reunification of Germany. With two years, the Soviet Union had broken up.
'A Beautiful Day'
Under a light drizzle, tens of thousands of people gathered to remember and celebrate the events of that day.
As evening fell, 27 European leaders and the four World War II allies gathered by the iconic Brandenburg Gate, led by German Chancellor Angela Merkel, who grew up in East Germany and was among the crowds who crossed to West Berlin on November 9, 1989.
U.S. Secretary of State Hillary Clinton walks past one of the domino stones outside the Brandenburg Gate in Berlin.
Earlier, accompanied by former Soviet leader Mikhail Gorbachev, she had retraced her steps, crossing Berlin's Bornholmer Bridge, the first formerly fortified checkpoint to open on the historic day.
The crowd chanted, "Gorby! Gorby!" as Merkel and Gorbachev shared an umbrella. Merkel told the former Soviet leader that he had "made this possible" because he "courageously let things happen."
The German leader said, "It is a beautiful day for us. When we in Germany celebrate this day together at the Brandenburg Gate this evening, then it is not only a special day for the Germans but it is also a celebration for all of Europe."
Later, Merkel joined U.S. Secretary of State Hillary Clinton and the leaders of France, Britain, and Russia for a symbolic walk through the Brandenburg Gate, which for 28 years was trapped in a no-man's land behind the wall.
Merkel told the crowd that November 9, 1989, was an "epic" moment in history and "one of the happiest moments" of her life.
She said the fall of the Berlin Wall "meant the Cold War had finally ended. It led to an era of unity, justice, and freedom in Germany and all of Europe. That makes the 9th of November a great, joyous day for all of us forever."
Merkel also noted that the Berlin celebrations honored "that brave engagement of our neighbors to the East."
"The unity of [Germany] would have been unthinkable without our neighbors in Central and Eastern Europe," she said. "For that we are and will remain thankful from the bottom of our hearts."
A Call For Unification
U.S. President Barack Obama did not attend the celebrations, but a taped video message from him was shown on a jumbo video screen.
He told the crowd, "November 9th, 1989, will always be remembered and cherished in the United States. Like so many Americans, I'll never forget the images of people tearing down the wall. There could be no clearer rebuke of tyranny. There could be no stronger affirmation of freedom."
Clinton praised the East Germans who decided to take their own fate in their hands, saying, "Tonight, we remember the Germans on both sides of the wall, but particularly the Germans in the East, who stood up and finally were able to say, 'No more! Freedom is our birthright, and we will take it by our own hands!' "
Russian President Dmitry Medvedev took the stage to say that "the role of the Soviet Union in that period was truly decisive" in ending communism.
He cited the reforms that in the late 1980s were gaining momentum in the communist Soviet Union and countries in Eastern Europe, within the Soviet sphere.
The Russian leader alluded to the distrust that still separates his country from the West with a reference to "our common Europe." He added that more must be done to clear old dividing lines.
"I would like to say here in Berlin that we all hope that we have left the period of confrontation in the past. The transition to a multi-polar world is very important for most countries, for all countries in Europe and in the world," he said.
How It Fell
The Berlin Wall stood for 28 years as perhaps the most potent symbol of the Cold War.
During 1989, pressure had been building on the East German government, with large street demonstrations showing growing discontent.
And then on November 9 of that year, a government spokesman announced that East Germans would be free to travel to the West.
The announcement -- which, as it turned out, was made earlier than planned -- sparked a rush to the border checkpoints. Crowds on the West Berlin side chanted, "Open the gate!"
As the number of people swelled, border officials finally threw open the barriers and people began to stream through to West Berlin.
West Berliners welcomed them with sweets and drinks, and parts of the city -- like tonight -- became one big street party.
Revolutions Of '89
In the fall of 1989, a singular wind of change swept across the continent, blowing down the Iron Curtain and revealing the public's yearning for freedom. Click here
for RFE/RL's look back at the year communism collapsed.