
Latest cruise ship extras: Anybody can do pools and kids' clubs. But these 10 recreational extras, such as this personal submarine from Crystal Esprit, are bringing the at-sea experience up a notch. Click through the gallery for more wild offerings:

Robot bartenders: Robo-bartenders helm the bar at the "mixology meets technology" Bionic Bar, found aboard select Royal Caribbean ships.

Racetrack: Satisfy your need for speed on Norwegian's new Norwegian Bliss, equipped with the largest racetrack at sea.

Snow Grotto: Chill out in Viking's "Snow Grotto," part of their ocean-sailing ships' spa complexes. Such cold therapy following a sauna or steam is inspired by Nordic wellness traditions.

Underwater lounge: The first of Ponant's six planned Blue Eye underwater lounges -- as depicted in this rendering -- debuted aboard its Le Laperouse ship in June 2018.

Sky bike: Put your pedal power to the test 150 feet above sea level on Carnival's SkyRide attraction, a fun feature aboard its two newest ships: the Carnival Vista and Carnival Horizon.

Skydiving simulator: Royal Caribbean stands out for its adventure-minded innovations such as the RipCord by iFLY attraction, a skydiving simulator that's available on its Quantum-class ships.

Ice Bar: Norwegian Cruise Line serves up frosty cocktails and an icy winter scene at its Skyy Vodka Ice Bar, found aboard the Norwegian Breakaway, Norwegian Getaway and Norwegian Epic.

Planetarium: Cunard Line's Queen Mary 2 comes equipped with the only full-sized planetarium at sea -- time your voyage right, and you might even find yourself sharing the view with a former astronaut.

Seawalk: Walk on water via Princess Cruises' SeaWalk feature (available on the Regal Princess, Royal Princess, and Majestic Princess), a glass-bottomed pathway that cantilevers the ships' side by 28 feet and overlooks the ocean waves some 130 feet below.


