A jimjilbang, or Korean-style sauna and bathhouse, Spa World hosts a variety of hot tubs, water massages, and specialty sauna rooms built to bombard you, supposedly, with healing, energy oscillating waves. Whatever the logic, it feels pretty good, and it’s more comfortable than doing 30 minutes on the treadmill. And there’s a smoking section, plus a New Age–y Ball Zone: a room filled with hot clay balls in which you lie after donning your yellow pajamas. Be forewarned, there’s a modest amount of public nakedness involved in the experience, but so soothing are Spa World’s many amenities that they more than offset the tension of having to disrobe.