Royal Caribbean pushes the limits of ship size more than any other cruise line. The Allure and Oasis of the Seas dwarf all other cruise ships, with a capacity of more than 5400 passengers each, vast internal atriums, big stage shows, ice rinks, rock-climbing walls, and even boxing rings. The range of activities makes most of Royal Caribbean’s ships solid picks for multi-generational vacations. The liner is also heavy into branding—Starbucks, Johnny Rockets, and Barbie all rear their corporate heads. The mood is relaxed, and dress codes aren’t doggedly enforced. A few amenities are missing, like self-service laundry rooms. Available itineraries span the globe, from the Caribbean to Southeast Asia.