Nov. 9 (Bloomberg) -- Chancellor Angela Merkel called it the “most joyful day in German history.” French President Nicolas Sarkozy drove from Paris to witness it, and Russian Prime Minister Vladimir Putin said it helped build trust.

World leaders gathered in the German capital today to mark the fall of the Berlin Wall 20 years ago, an event that spurred the collapse of communism across eastern Europe, the end of the Cold War and German reunification within less than a year.

“It was one of the happiest moments of my life,” Merkel, who grew up in East Germany, told crowds at the Brandenburg Gate in central Berlin as the rain poured down. “We must also overcome the borders of our own time, just as we managed to do in 1989 in this divided city.”

Russian President Dmitry Medvedev, British Prime Minister Gordon Brown and U.S. Secretary of State Hillary Clinton were among those who joined Merkel at the Brandenburg Gate, which once loomed over the barbed-wire barrier that divided East and West Berlin for 28 years until the night of Nov. 9, 1989.

Earlier, Merkel and the representatives of the four powers that controlled Berlin after World War II -- Britain, France, the U.S. and Russia -- symbolically walked through the gate.

The climax of the “Fest der Freiheit,” or Freedom Festival, featured 1,000 giant dominoes made to look like Wall segments lining a 1.5 kilometer (0.9 mile) stretch of the original barrier. Lech Walesa, leader of the Solidarity movement who went on to become Polish president, toppled the first domino, setting off a chain across the city.

‘No Clearer Rebuke’

“There could be no clearer rebuke of tyranny; there could be no stronger affirmation of freedom,” President Barack Obama said in a recorded video message played to crowds.

“This wall was torn down by the greatest force of all: the unbreakable spirit of the men and women of Berlin,” Brown said. He vowed that Britain “will always be at the heart of Europe” and pledged to strive for an end to nuclear proliferation, “extreme poverty” and climate “catastrophe.”

Medvedev said he hoped the “era of confrontation is over” and urged greater co-operation to fight the economic crisis and tackle joint threats such as terrorism.

“We are brothers,” Sarkozy said in German at the end of his speech. “We are Berlin.”

Peaceful Protests

The commemorations began with a morning service at the Gethsemane Church in Berlin’s east, center of the peaceful protest movement that helped bring down the Wall.

From there, Merkel, Walesa and former Soviet leader Mikhail Gorbachev, architect of the policies that loosened Moscow’s grip over its East European dominions, walked over the bridge at Bornholmer Strasse, a former east-west crossing point. That was where thousands of East Berliners amassed 20 years ago demanding passage to the West, after an unexpected announcement by the communist government allowing visa-free travel.

While there was confusion about the law, border guards at the checkpoint were unable to turn back the crowd and gave way, triggering the breakdown of the heavily guarded border.

“We weren’t the first in Germany, but we were there when the Cold War collapsed,” Merkel said at the spot where she herself crossed into the West when the wall came down.

Bornholmer Strasse was the epicenter of events 20 years ago, said Jan Techau, an analyst at the German Council on Foreign Relations.

“After it was really open, people immediately began to attack the Wall itself, to chisel away at it,” Techau said.

Sarkozy’s Pickaxe

Among them was a 34-year-old Sarkozy, then a lawmaker in France’s lower house of parliament. He had jumped in a car that morning with Alain Juppe, a future prime minister, to witness the change they felt was coming. When they arrived, the Wall was already being breached and Sarkozy joined in, he said on his official Facebook Internet site.

“We headed for Checkpoint Charlie to see the eastern side of the city and finally confront this Wall and I was able to take a pickaxe to it,” Sarkozy wrote. He attached a photograph showing him in front of the Wall. Juppe later said on his blog he couldn’t be certain about the date.

The images beamed around the world in 1989 of Germans and others hacking away at the Wall often took place with the Brandenburg Gate as the backdrop. Daniel Barenboim conducted the Staatskapelle Berlin in front of the Gate today, before fireworks and a dinner for leaders hosted by Merkel.

‘Had to Happen’

“What had to happen, happened,” Putin, who served as a KGB agent in East Germany at the time, said of the events of 1989 and 1990 on Russia’s NTV television yesterday. “Dividing the nation had no future.”

The commemoration events have also brought together many of the key players who shaped events in 1989. On Oct. 31, former President George H.W. Bush joined his German counterpart from the time, Chancellor Helmut Kohl, and Gorbachev at a ceremony in central Berlin.

Merkel, the first chancellor from former East Germany, said that Kohl’s promise to bring “flourishing landscapes” in the east has come to pass over the past 20 years.

“Things have happened over that period that we simply wouldn’t have thought possible,” she told ARD television.

To contact the reporter on this story: Patrick Donahue in Berlin at at pdonahue1@bloomberg.net.

Last Updated: November 9, 2009 14:54 EST