Spas with upscale

Chicago, Illinois

Thermal baths and spa rituals in a restored 1902 factory in West Town, Chicago, open daily for adults-only soaking and massage packages.

Toronto, Ontario

A reservation-only thermal bath circuit in a 1912 Edwardian building in Toronto, with eight pools, a dry sauna, steam room and massage treatments.

Austin, Texas

Hotel spa inside W Austin with seven treatment rooms, 22 services including couples massage, and access to the rooftop WET pool deck.

Bagno Vignoni, Tuscany

Hotel spa in a 15th-century Bagno Vignoni palazzo with a thermal pool fed by the village's natural hot springs, open to day visitors.

Marbella, Andalusia

Hotel day spa at Amàre Marbella with a hydrotherapy circuit, facial treatments, massages and couples options, open daily 11am-7pm.

Chiang Mai

Hotel spa at Anantara Chiang Mai with steam rooms, sauna and couples' suites, built around the signature Lanna Ritual massage overlooking the riverfront pool.

Washington, D.C., District of Columbia

Hotel spa inside the Watergate Hotel with a retro indoor pool, whirlpool, dry sauna and steam room, plus a day pass for treatments and amenities.

Aspen, Colorado

A reservation-only Aspen studio offering private sound, energy and subconscious-journey sessions instead of classic spa treatments.

Palm Springs, California

Adults-only hot springs resort on Miracle Hill in Desert Hot Springs with private mineral tubs, a Finnish sauna, salt room and 35 spa treatments.

Tenerife, Canary Islands

A hotel spa at Bahía del Duque in Costa Adeje with an outdoor seawater thalassotherapy circuit, hammam, saunas and a cold plunge, open to day visitors.

Nashville, Tennessee

Upscale hotel spa inside 1 Hotel Nashville with 38 treatments, an infrared sauna wrap, and an 18-plus minimum age; no day pass offered.

Miami, Florida

Day spa in the Sherry Frontenac Hotel's lower lobby in Miami Beach, with sauna, steam, cold plunge and thermal pool alongside massage treatments.

Orlando, Florida

A six-treatment-room hotel spa at Wyndham Grand Orlando with 54 services, a hot tub and relaxation lounge, open daily 10am–6pm.

Plainfield, Indiana

Day spa in Plainfield, IN offering facials, massages and body-sculpting treatments alongside a sauna, steam room and thermal pool, reservation required.

Miami, Florida

A beachfront resort spa in North Beach, Miami with cryotherapy, a floating salt bath, sauna, steam and a cold plunge, open to walk-ins and day-pass guests.

Prague

A day spa near Wenceslas Square in Nové Město offering massages, facials and thermal pool access with day passes for walk-ins.

San Francisco, California

A hotel spa at Fort Baker near Sausalito for Cavallo Point guests, with a meditation pool, Zen garden, infrared sauna and outdoor Jacuzzis.

Istanbul

A working Ottoman hammam built in 1741 in Istanbul's Fatih district, offering traditional bath rituals with no day-pass option, only full treatments.

Chicago, Illinois

Adults-only hotel spa in River North with a 67-foot pool, multiple sauna and steam rooms, and day passes for non-guests.

Los Angeles, California

A day spa inside the Westin Bonaventure in Downtown LA, with massages, facials, body treatments, sauna and a relaxation lounge.

Miami, Florida

Hotel spa inside Dua Miami, Autograph Collection in Brickell, open daily 9am-6pm, with sauna, steam room, cold plunge and couples massage rooms.

Florence, Tuscany

A 650-square-meter spa inside a 14th-century Florence monastery, with thermal pool, guesthouse rooms, bistro and day-pass access.

Tabernash, Colorado

A resort spa at Devil's Thumb Ranch in Tabernash, Colorado, open only to overnight guests, with a geothermal pool, hot tub and couples treatments.

Jackson Hole, Wyoming

A day spa next to the Trailborn hotel in Jackson Hole with an outdoor pool deck, salt lounge and day passes for walk-in soaks or treatments.