Spas with upscale

Amsterdam, North Holland

A day spa inside a former bank vault in central Amsterdam, with pool, whirlpool and a canal-view gym; adults-only, day pass by reservation.

Minneapolis, Minnesota

Hotel spa inside Hotel Ivy in downtown Minneapolis, offering massages, facials, body treatments and a steam room on the hotel's second floor.

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.

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.

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.

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.

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.

The Hamptons, New York

Oceanfront resort spa in Montauk with a seawater and marine-based treatment menu, hydrotherapy, contrast bathing, and a heated saltwater pool.

Doha

Hotel spa at The Westin Doha with some of the city's largest wet facilities, accessible to hotel guests and members only, no day passes sold.

Opatija, Primorje-Gorski Kotar

A 5-star hotel spa in Opatija with a sauna centre, seawater pools and couples treatments, open only to Hotel Ambasador guests.

Velingrad, Pazardzhik

Hotel spa in Velingrad with mineral-water pools, saunas, steam rooms and a hammam spread over 4,000 square metres; day passes are available.

Tucson, Arizona

Hotel spa at Loews Ventana Canyon Resort, Tucson, with eight treatment rooms, an adults-only pool, and a 24-hour fitness center; open daily 9am–6pm.

Paris, Île-de-France

A 4-star hotel spa in Paris's 15th arrondissement with a pool, hammam and fitness room, open to day-pass visitors as well as hotel guests.

Ein Bokek, Southern District

Hotel spa on the Dead Sea shore in Ein Bokek with a heated mineral-water pool, sulphur pools, hammam and sauna; day passes open to adults 16 and up.

Honolulu, Hawaii

A beachfront Waikiki hotel with a pool, fitness center and yoga sessions, open to guests staying at the OUTRIGGER Reef.

Nashville, Tennessee

A full-service hotel spa on the fourth floor of Omni Nashville, downtown, offering massages, facials, salon services and a rooftop pool, open to non-guests via

Edinburgh, Scotland

One Spa is an adults-only day spa in Edinburgh's city centre with a rooftop Hydropool, thermal suite and day-pass access.

Scottsdale, Arizona

Adults-only resort spa at the Andaz Scottsdale with treatment suites, a private pool, fitness center and cabana bookings, day pass available.

Park City, Utah

A 14-room hotel spa at Westgate Park City Resort with a waterfall, sauna, steam room and thermal pools, open daily 9:30am-6:30pm.

Lombok, West Nusa Tenggara

A hotel-guest-only wellness room at Rascals in Kuta, Lombok, with a traditional sauna, dual ice baths and a magnesium pool, open daily 8am–9:30pm.

Denver, Colorado

A 14,000-square-foot hotel spa inside Gaylord Rockies in Aurora, offering massages, facials, body treatments and a couples room, adults only.

Nashville, Tennessee

Day spa and medical spa on the third floor of The Westin Nashville downtown, with nine treatment rooms, a dry cedar sauna, steam showers and walk-in access to

Napa Valley, California

Hotel day spa atop the Archer in downtown Napa with a water deck, fitness studio access and treatment rooms; reservations required.

Jackson Hole, Wyoming

A Jackson Hole facility pairing physical therapy, acupuncture and massage with a climbing wall, salt room, infrared sauna and sound healing, open to day-pass