German Chancellor Angela Merkel and America's last Cold War leader called Friday for lasting transatlantic friendship as the US embassy in Berlin reopened on the site it last occupied in 1941.
Former president George H.W. Bush said the new mission, built beside the Brandenburg Gate in the former no man's land that divided West and East Berlin, "marked the symbolic rebirth" of US-German ties.
The old embassy was reduced to ruins by World War II air raids and later razed by East German authorities to make space for the Berlin Wall.
Bush, who was in the White House when the Wall fell in 1989, said nearly two decades after he championed reunification, the prospects for cooperation between Washington and Berlin were now limitless.
"Let history record that Germany and America took the decisive action that allowed a torn nation to heal.
"Our ties are stronger than ever and the conditions for friendship are 'ceiling and visibility unlimited'," he said, borrowing an aviation term.
He praised Germans for their determination to become one nation again and paid tribute to former chancellor Helmut Kohl and Mikhail Gorbachev, calling the last Soviet leader "our adversary-cum-partner".
Merkel, the first German chancellor to grow up in East Germany, said at times unity had seemed impossible but the United States helped it happen.
"The return of the US embassy to the Brandenburg Gate is a historic moment. I lived just around the corner from here and for many years I did not think it would ever be possible to walk through the Brandenburg Gate.
"I thank president Bush for the role the United States played. We will always protect our friendship. We take your concerns seriously."
The nostalgia-laden festivities at the new mission that took four years and 130 million dollars (82.8 million euros) to build ended with fireworks and a barbecue, despite drizzling rain.
Guests watched old footage of former US presidents pledging solidarity with Germans during the Cold War, including Ronald Reagan's famous 1987 plea: "Mr Gorbachev, tear down this wall!"
Germans have welcomed the fact that the embassy completes the reconstruction of Pariser Platz, the grand square that was flattened during World War II and lay barren during the Cold War.
Artist Katherine Mark, who attended the opening, told AFP: "The Americans must be here, it shows that we are a world city, not a village."
But the return to the pre-war address, decided in the early 1990s, also made for years of controversy as Berliners objected both to the aesthetics of the building and US security demands for the site.
The United States initially insisted on a 30-metre (100-foot) security perimeter around the embassy, something that would have required a central street to be moved and encroached on a historic park.
Berlin authorities accused the Americans of riding roughshod over the city's landscape while US officials said the Germans appeared ungrateful after four decades of protection during the Cold War.
Eventually the State Department settled for a slimmer buffer zone.
The Sueddeutsche Zeitung has mockingly called the stark, imposing building with its extra-thick walls and bullet-proof windows "Fort Knox at the Brandenburg Gate."
US diplomats have defended the design and said the embassy is a testament to past support for Germany and present, improved ties following the row over the US-led invasion of Iraq in 2003.
Berlin's coordinator for US-German relations, Karsten Voigt, pointed out that if many Germans still had little time for US president George W. Bush, his father was a popular figure because of his fulsome support for reunification.
The elder Bush this week recalled battling to convince former French president Francois Mitterrand and ex-British prime minister Margaret Thatcher that the time had come to unite West and East Germany.
"I can understand France and England being concerned but ... I thought the time was right to show our confidence by encouraging reunification.
"I dealt with Mrs Thatcher very carefully, that is how I always dealt with her. Francois, you know he said 'I like Germany so much I think there should be two of them'. They were not enthusiastic."
