Royal Caribbean is mandating vaccination for those 12 and older on Serenade of the Seas sailings from Seattle. The ship is very easy to navigate, with indoor public rooms concentrated on decks five and six and more-active areas - sports deck, pools, spa, fitness center - on decks 11 and 12. The decorating scheme itself emphasizes elegance, grace, and beauty, and creates quite a harmonious environment. The effect is simply dazzling - and there are remarkable views from nearly every public room. Royal Caribbean carries through this ship the Radiance-class' most interesting distinction is the nearly three acres of exterior glass employed in its design - including glass elevators with ocean views - that incorporates the outdoors, beautifully, onboard. It's a good choice for a wide range of traveler - including families, singles, couples and groups. Serenade of the Seas' greatest strength is that it offers plenty of options, from dining to entertainment, and yet remains a mid-sized ship. That flexibility extends to the onboard milieu. The 90,090-ton, 2,100-passenger vessel fits just within Panamax measurements (with one foot on either side to spare), which means it, like Radiance, Brilliance and Jewel of the Seas, has maximum geographic flexibility and can sail to and from just about any region. Serenade of the Seas is the third Radiance-class ship in Royal Caribbean's fleet.