Grunwald. It's near the polish German border and was the site of a lot of conflict between the Teutons and the poles during the crusades. The poles were Christian or pagan, depending on where, but few were, I believe, catholic. Therefore, it's crusade time. And one of the biggest actions occurred at grunwald. They even made a (polish) movie out of the (real) story. The castle is a tourist place now, which makes it lack the atmosphere you get from those sorts of places often.