Royal Caribbean’s Anthem of the Seas has a lot of impressive sights and sounds — from a skydiving simulator to a show lounge that's home to cover bands — but the most surprising sight of all might be the "stowaway" piano player. This pianist entertains guests throughout the ship, traveling and playing everywhere from the atrium to the pool deck and even in the glass-fronted elevators. The custom-made piano sits on wheels and is loaded with bells and whistles — literally — as well as a microphone and a candelabra. The schedule isn't printed in the daily calendar of performances, so guests find themselves stumbling upon him at random times during their sailing.

Now, this crowd-pleasing attraction is coming to some of the line's other ships, with both Harmony of the Seas and Ovation of the Seas launching with their own "stowaways" this spring.