Germany - Berlin

This postcard shows Berlin, the capital of Germany. Sometimes I wonder, why haven't I visited Berlin yet, if I've been to Germany for so many times and Berlin is so close to the Polish border?
By the way, several days ago I read that now Berlin regrets destroying their wall totally, because many tourists want to see it, so now they have to use special guided tour and they can learn, where exactly the wall used to be. Anyway, I think it's much better without the wall.