What: A sprawling bi-level oasis at the Cosmopolitan of Las Vegas, with separate men's and women's wet areas featuring steam rooms, saunas, and whirlpools. The star is the 1,100-square-foot hammam, heated to 105 degrees.
The look: Inspired by the Mojave Desert, the spa is constructed of 420 tons of salmon-hued sandstone. Guests enter through "the space between," a narrow tunnel that ends at a 22-foot waterfall.
Who goes: Weekends, affluent hipsters prepping for (or recovering from) a night out. Locals dominate the weekday scene.
The treatment: The Red Flower Hammam Experience is a modern spin on the classic, starting with ritual bathing and vigorous scrubbing on the mother stone, followed by a clay wrap and massage.
P.S.: Sahra has an Aromapothecary iPad app that allows you to create customized massages, scrubs, and baths.