With new cruise ships hitting the water every year, it seems that each boat boasts more extravagant amenities than the last. If you’re an avid cruiser, you might think this is nothing new — cruise lines are infamous for pushing the limits on prestige and luxury.

However, some of these onboard attractions are so incredible, wild and unexpected that you’ll be left wondering why anyone would ditch the deck for dry land.

Skydiving Simulators

You probably shouldn’t jump from a cruise ship with a parachute on, but Royal Caribbean’s Quantum-class ships, including Anthem of the Seas, offer a once-in-a-lifetime opportunity to get your free-fall on and pseudo-skydive without so much as leaving the deck.

Using RipCord technology by iFly, Royal Caribbean ups the ante in cruise ship amenities by allowing passengers the thrilling experience of skydiving on the open seas via a wind tunnel right on top of the stern of the ship. Not only is this the first ever skydiving simulator on a cruise ship, but the 23-foot wind chamber on Royal Caribbean ships is arguably one of the most amazing installations in the world.

First-time flights last between 2 and 6 minutes and amateur flyers can expect personalized training, plenty of hands-on instruction, and all the gear needed for a safe flight. When it’s time to dive, brace yourself for a gravity-defying, scenic skydiving experience you’ll never forget.

Waterslides

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Hopping aboard a cruise ship usually means soaking in ocean panoramas from balconies or pools, but if you're an adventure-seeking, water-loving cruiser, you can also get your adrenaline fix from cruise ship waterslides and attractions.

But we’re not just talking about your everyday water feature. Cruise ships are constantly outdoing each other for the biggest, wildest offshore water attractions.

Royal Caribbean ships, like Harmony of the Seas and Symphony of the Seas, top the charts for the tallest water slide at sea by offering a 10-story water slide on board, aptly named Ultimate Abyss. But if you're looking for other epic free-falls, Carnival Cruise Lines also has a four-story plunge and Norwegian Cruise Lines has towering side-by-side slides so you can race your BFF to the bottom.

Lastly, don't count Disney out — Disney’s popular cruise lines, Disney Dream and Disney Fantasy, boast water slides and “aqua coasters” with trap doors, three-story vertical drops, and dizzying translucent tubes that shoot you 20 feet over the side of the ship (safely, of course).

Go-Kart Racing

Yep, you read that right, you can burn rubber aboard two new Norwegian Cruise Lines ships. Norwegian really outdid themselves when they installed the world’s first at sea go-kart track aboard one of their boats in 2017, but that didn’t stop them from building a second, larger, two-level racetrack on board the new, 167,800-ton Norwegian Bliss — the first of its kind on a North American ship.

So that means if you jump aboard the Norwegian Bliss, you can pass time by putting the pedal to the metal on a 1,000-feet long go-kart course, 19 levels above the ocean. Don't fret if racing cars isn't your expertise, the cars have beginner, intermediate and advanced settings with a “turbo boost” option on each lap. For those with a serious need for speed, the advanced speed setting allows drivers to reach a whopping 30 mph.

Explore a Planetarium

Interested in a trip to space? Nothing beats stepping outside to a sky full of stars, that is, until the newest Viking Ocean Cruise ship, Viking Orion, debuted a high-tech, true-to-life, at-sea planetarium. The Explorers’ Dome, which features 3D films like “Journey to Space” and “Under the Arctic Sky,” isn’t just a neat place to stare at stars, it’s also the highest-definition 7K planetarium in the world.

And if having an onboard planetarium isn’t enough to peak your curiosity, the Viking Orion also houses a resident, real-life astronomer, Howard Parkin.  So we have to ask, what better way to learn about the star-filled sky, than by participating in a stargazing session hundreds of miles offshore with an astronomer?