The punch line

It's a famous story in Germany.

When JFK travelled to a then-divided Berlin, he gave a speech which made history for more than one reason. I haven't got the details at the moment, but he ended declaring his solidarity with the Berliners by saying "Ich bin ein Berliner," which, in Berlin, means "I am a Berliner." However, in the rest of Germany, it means "I am a jelly donut." Berliners are jelly donuts. Germans talk about the mix-up to this day. They love JFK for it and now in Berlin there is a big school named after him.