Enjoy Christmas-themed entertainment onboard Explore Frankfurt, a city of contrasts with both modern and historical influences Cruise the Rhine in Mainz with stunning vistas of hilltop castles and villages Visit Koblenz, located at the confluence of the "German Corner" where the Rhine & Moselle Rivers meet Sail on the legendary Rhine to Cologne, capital of the Rhineland See symbolic Rheinturm Tower in Dusseldorf, one of the most recognizable landmarks in the city In Amsterdam, board a glass-top boat and cruise the winding canals