Former US president John F. Kennedy made history 50 years ago as he stood on the front line of the Cold War and told the world "Ich bin ein Berliner" (I am a Berliner).
The young US leader reached the hearts and souls of an isolated and anxious city and set a benchmark for political discourse that many successors have tried to match.
US President Barack Obama, who visited Berlin as a front-running candidate in 2008, returns this week against a backdrop of significantly more sober transatlantic relations.
Kennedy's celebrated statement came on June 26, 1963, almost two years after communist authorities began building the Berlin Wall.
"All free men, wherever they may live, are citizens of Berlin, and, therefore, as a free man, I take pride in the words 'Ich bin ein Berliner'," Kennedy said during an eight-hour visit to the former and future capital.
He spoke to a rapturous crowd in front of the West Berlin city hall on a square subsequently renamed John-F.-Kennedy-Platz.
Current mayor Klaus Wowereit said those words "won back the hearts" of Berliners who had felt let down when the US failed to react as the wall was built.
Ever since, visiting US leaders have tried to use Berlin's unique backdrop to highlight their own remarks.
The most memorable were comments by Ronald Reagan on June 12, 1987 before the iconic Brandenburg Gate on the East-West border.
Protected by bullet-proof glass and surrounded by West German and US flags, Reagan challenged Soviet counterpart Mikhail Gorbachev, saying: "If you seek peace ... come here to this gate. Mr. Gorbachev, open this gate! Mr. Gorbachev, tear down this wall!"
Before Reagan, recently-elected president Richard Nixon stood on the hood of his limousine on February 27, 1969 shaking hands with West Berliners who came to greet him.
Speaking at the end of the motorcade, Nixon acknowledged: "Sometimes you must feel that you are very much alone.
"But always remember that we are with you, and always remember that people who are free and who want to be free around the world are with you. In the sense that the people of Berlin stand for freedom and peace, all the people of the world are truly Berliners."
On July 12, 1994 Bill Clinton addressed a city that had been reunited for almost four years, and speaking at an open Brandenburg Gate, dared to emulate his idol Kennedy with comments in German.
Clinton said: "Nothing will stop us. All things are possible. Nichts wird uns aufhalten. Alles ist moeglich. Berlin ist frei. Berlin is free."