Regularly ranked among the world's most luxurious lines, Germany-based Hapag-Lloyd Cruises pulls out all the stops on its flagship Europa. The 400-passenger stunner gets points for one of the highest passenger-to-space ratios, without skimping on big-ship amenities. For foodies, the restaurant helmed by Michelin-starred Chef Dieter Muller is reason enough to set sail, while others are drawn by the world-spanning itineraries and highbrow theme cruises. The ship also caters almost exclusively to a German-speaking clientele.