In a twist — well, several of them as it turns out — Royal Caribbean's new mega ship Harmony of the Seas offers something totally different: the Ultimate Abyss. The "dry slide" is a perfect ride for adventure junkies, plunging those who dare down 10 stories from Deck 16 to the Boardwalk neighborhood on Deck 6. I held on tight and took a turn (it was so much fun that I went a few times, actually) to give you the inside scoop on what to expect.