What: A discreet curved staircase just past the Hôtel La Mamounia's upscale stores leads to a 27,000-square-foot subterranean sanctum within the city's medina walls.
The look: A series of low-lit, starkly minimalist rooms, with a shallow, decorative pool rimmed with Art Deco-esque lanterns. There are nine treatment rooms, a hammam (for men), a steam room (for women), and an unfussy seating area with cushy leather loungers. Outdoor treatments are offered in summer.
Who goes: A well-heeled, predominantly international clientele. Day, week, and monthly passes are available for fuller immersion.
The treatment: The many massages, scrubs, and facials are made more fragrant with local materials, including black soap, Rhassoul clay, argan oil, and orange-blossom water.
P.S.: The low lighting and unmarked doors can be problematicunless you're escorted you might, as this reviewer did, walk into someone else's treatment room (massages, $171).