Heidelberg's a blast! This German university town has something about it that simply says "style." It also has a history of revolutionary ideas, religious schisms, destruction, anarchy and heroic restoration.
This may be why it attracts 3 million tourists a year.
There's a thoroughly imposing, partially ruined and utterly Teutonic schloss (castle) that looms large on a central peak overlooking the River Neckar. There are mysterious little cobbled alleys that make the perfect set for a fantastic game of hide-and-seek (or a remake of "The Cabinet of Dr. Caligari"). There are street markets and courtyard cafes and musty subterranean beer halls. The buskers play harps or violins.