The castle hopping highlight for many is in Heidelberg. A cable car carries you up to this massive complex of fortresses. Achtung — you’ll likely be storming the castle with armies of tourists, especially if you go in the busy summer months. The castle attracts about one million tourists a year. We took the family-friendly tour, where kids play jousting games and imagine life as a knight. Playing dungeons and dragons in a real castle? Could there be a better way to learn about history for kids? We don’t think so.