Actually, I lived in Ludwigshafen, Germany. It was like 30minutes away from Heidelberg, Germany, where they have the American Base Army in German.
In here, it located the University of Heidelberg, one of the most famous university in the world. Heidelberg is the only city in German was not been bombed by the Ally during the World Ward II. Thus when you come to this city you would see an old German house which you saw in all the Disney movie that you have watched in your childhood :)
To me, Heidelberg is one of the the best city in German, that worths a visit of yours trip :)