American Express, Discover, MasterCard, Visa
It may lack the democratic bustle of Spa Castle, but this Tribeca newcomer—the first North American offshoot of a Spanish mini-chain—brings a certain grandeur to the urban shvitz tradition. In exchange for the steepish cost of entry, you get small groups instead of gawky packs (about 25 people per 90-minute, $75 block), plus access to a staggering suite of amenities. Pools of hot, warm, cold, and ice water, modeled after Greco-Roman and Ottoman rituals, glow in the basement grotto along with jet and salt baths and a steamy hammam. You can tack on a massage (fifteen minutes to an hour and two to four hands for $95 to $210) or book a special treatment—a private bath enhanced with milk, citrus juice, olive oil, cava, or red wine, plus a massage and access to the thermal baths, runs $450 to $500.
Indoor surfing, spinning lovefests, a luxurious pig-placenta facial, and more.