Because they sail from American ports, both Royal Caribbean (RCL) and Carnival Cruise Line ... and I’ve heard the adults only rule on the serenity deck is not strictly enforced.

Couples looking to escape the crowds will find a haven on the adults-only Serenity sun deck. Thrill-seekers will enjoy the SkyRide, the SkyCourse and --first on Carnival Panorama -- the SkyZone ...