Harmony of the Seas | Adventure x 1000. With 18 decks of thrills, tech innovations, and luxurious amenities – Harmony of the Seas redefines what it means to adventure in comfort and style. Start the afternoon off with a daring slide down the Ultimate Abyss and top it off with a challenging ascent on the rock climbing wall. Head below deck for some R&R and a drink at the high-tech Bionic Bar. It’s all this and more when you cruise with Royal Caribbean onboard Harmony of the Seas.