People from all walks of life streamed to the German capital's Victory Column memorial at the heart of the city's Tiergarten park hoping for a glimpse of the popular US senator from Illinois.
“Thank you to the citizens of Berlin and to the people of Germany,” Obama told the crowd to wild applause. "Tonight, I speak to you not as a candidate for president, but as a citizen – a proud citizen of the United States, and a fellow citizen of the world.”
As the sun set on the German capital, the predominately younger audience of Berliners listened intently to Obama speak of the common problems facing Europe and America.
“As we speak, cars in Boston and factories in Beijing are melting the ice caps in the Arctic, shrinking coastlines in the Atlantic, and bringing drought to farms from Kansas to Kenya,” Obama said.
“Poorly secured nuclear material in the former Soviet Union, or secrets from a scientist in Pakistan could help build a bomb that detonates in Paris. The poppies in Afghanistan become the heroin in Berlin. The poverty and violence in Somalia breeds the terror of tomorrow. The genocide in Darfur shames the conscience of us all.”
German television broadcast the speech live, as some 1,000 police officers, US Secret Service and private security guards were mobilized for the visit.
Prior to his address, Berliners gave the event a festival atmosphere, grilling sausages and selling beer near the site of the speech, which has frequently been used for large public gatherings.
The massive show of support underscored how deeply dissatisfied many Germans are with the leadership of US President George W. Bush, who remains unpopular in Europe for his decision to invade Iraq and his apparent reluctance to tackle issues like global warming.
Uwe Bley came all the way from the northern port city of Hamburg with his wife to see Obama on Thursday. "He can't change much from here," the 60-year-old told The Local, expressing his desire for the presidential candidate to take America in a new direction. "But he's the new hope now."
Obama told the massive crowd near the former course of the old Berlin Wall that humanity faced a perilous turning point, and it was time to build "a world that stands as one."
"The greatest danger of all is to allow new walls to divide us from one another," said Obama, who has scorched through US politics at lightning speed to challenge Republican John McCain for the White House in November's election.
The audacious speech took the White House race out of US borders in a way never seen before, and was designed to portray Obama as a leader with unique global appeal.
"The walls between old allies on either side of the Atlantic cannot stand," he said, referring to festering divisions between Europe and the United States opened up by the US-led invasion of Iraq in 2003.
"The walls between the countries with the most and those with the least cannot stand. The walls between races and tribes; natives and immigrants; Christian and Muslim and Jew cannot stand. These now are the walls we must tear down," Obama said, drawing loud cheers and applause.
Obama's speech was a clear echo of former US president Ronald Reagan's call to then Soviet leader Mikhael Gorbachev in Berlin in 1987 to "tear down this wall," before the fall of communism.
"It was a good speech, nicely geared to an international audience," American Berlin resident Michael Goodhart, 38, told The Local after the event. "It's impressive that he can draw such a crowd here," he said. "Obama represents such a stark change - in his age, look and policies."