Mr President shows his face in Berlin
It all started with John F. Kennedy, the first US president to visit West Berlin.
Symbol of the free West
A US flag in front of the Brandenburg Gate - for many years, that really meant something. During the Cold War, West Berlin was an enclave of the West in the middle of the communist GDR. It was important for the US to have a presence there. John F. Kennedy was the first US President to visit the free part of Berlin 50 years ago.
'Ich bin ein Berliner'
Thousands flocked to West Berlin's town hall to hear Kennedy's speech. Berlin's then-mayor Willy Brandt hosted the US president, who ended his speech with the famous line "Ich bin ein Berliner." His message: the US was ready to defend the free West Berlin at any cost.
'The brave people of Berlin'
Richard Nixon came to West Berlin in February 1969. Before he arrived, he had written to Chancellor Kurt Georg Kiesinger a letter expressing his wish to visit the "brave people of Berlin." Nixon as well as Kiesinger favored a strong alliance between the US and Germany.
'Whatever happens, Berlin will remain free'
In July 1978, 150,000 Berliners lined the pavements of West Berlin's Kurfürstendamm to see US President Jimmy Carter and German Chancellor Helmut Schmidt. When Carter arrived at Berlin's Tempelhof airport he said "whatever happens, Berlin will remain free." On a personal level, Carter and Schmidt didn't get on at all. Both leaders made disparaging remarks about each other after the visit.
"Mr. Gorbachev, tear down this wall"
During his first visit to Berlin in 1982, US President Ronald Reagan visited the Checkpoint Charlie border crossing which separated West and East Berlin with Berlin mayor Richard von Weizsäcker and Chancellor Helmut Schmidt. But it wasn't until 1987 that Reagan addressed the people of Berlin at the Brandenburg Gate, with the famous line "Mr. Gorbachev, tear down this wall."
'Berlin ist frei'
In 1994, Bill Clinton was the first US president to visit reunified Berlin. At the end of his speech, he said in German: "Alles ist möglich. Berlin ist frei." ("everything's possible. Berlin is free.") His predecessor George Bush did come to Germany after reunification in 1990, but he only went to Chancellor Helmut Kohl's private residence in the south-western town of Ludwigshafen.
'Stop Bush'
George Bush's son, George W. Bush, came to Berlin twice. In 2002, he was met with protesters shouting slogans and waving placards saying "Stop Bush" and "Warmongers not welcome." It was a lot quieter when he came again and spoke in the Bundestag in 2008, emphasizing the common objectives of the US and Germany.
Obama leaves it late
Barack Obama did not visit Berlin during his first four years as president. He did come to Berlin as a presidential candidate in 2008. Around 200,000 people cheered him on as he spoke at the Victory Column in the German capital.