Well, it's hard to say where to start first. When you are looking for history and museums, the big cities are probably a good start. But you should not neglect the smaller towns. But I guess Munich is a really good start. Berlin obviously offers a lot of history, museums, culture to offer as well ... but apart from that most parts of the city imho are really ugly. But I guess most bigger cities don't look as overseas tourists might expect, as most of them had been totally destroyed in the war.