At the opulent, multidomed Emirates Palace (West Corniche; 971-2/690-8885; emiratespalace.com; doubles from $763; spa treatments from $190), the recently opened Anantara Spa is upping the ante on luxury in the ultra-competitive world of extravagant Middle Eastern hotels. Inside the spa, intricate Moroccan Zelish tile work lines the floors beneath a domed ceiling dotted with fiber-optic lights that glow cobalt blue; a cavernous private treatment complex has its own dining room and a hammam with heated marble double beds; another suite is devoted to Vichy showers. Don’t miss the Gateway to Arabia massage and wrap, which uses local ingredients such as black olive soap, royal-jelly honey, and rassoul mud—then cool off in the ice cave. Beyond the spa, the hotel’s hallways shimmer with gold and silver mosaic tiles beneath a thousand Swarovski chandeliers, and even guests in standard rooms enjoy private butlers, Hermès amenities, transportation via helicopter or Maybach, and restaurants serving cuisine ranging from Italian to Lebanese. It’s no wonder the $3 billion, 394-room hotel is among the most expensive ever built (you don’t need to do the math; that works out to an average of $7.6 million per room). For the best one in the palace, book the 1,185-square-foot Khaleej Suite, overlooking the Persian Gulf—it’s closest to the spa.