The Spa at Aria
In contrast to the intimate Spa at Mandarin Oriental, the cavernous space of the 80,000-square-foot Spa at Aria is what makes it particularly luxurious. Guests can completely remove themselves from the fray and relax on the heated-stone ganbanyoku beds, on which you lie to purge toxins and stimulate circulation (they're the only such beds in the U.S.). You can also try the Shio Salt Room, in which you lie on comfortable lounges and breathe in the therapeutic salt air, or a co-ed pool that looks over the resort’s outdoor pool scene. If you’re going with a significant other, meet up in the area between the men’s and women’s sides, in the balcony pool lounge, where you can canoodle while overlooking the resort’s rowdier pool scene below.