Spas with relaxation lounge

Charleston, South Carolina

Private contrast-therapy suites with infrared sauna, cold plunge and vitamin C shower in West Ashley, Charleston, by reservation.

Orlando, Florida

Adults-only hotel spa at Disney's Grand Floridian Resort with massage, salon services and a fitness center, open to walk-ins daily 9am-6pm.

Denver, Colorado

A 6,000-square-foot hotel spa in downtown Denver's Granite Tower, open to day-pass visitors 18 and older for $40 to $75.

Calistoga, California

Hotel spa in downtown Healdsburg with a garden patio, jacuzzi and pool access, open daily 9am-5pm for guests and day visitors.

Los Angeles, California

Four Seasons hotel spa in Beverly Hills with a steam room, rooftop pool, fitness center and eight treatments, open daily, day passes available.

Hunter Valley, New South Wales

Large day spa at Chateau Elan in Hunter Valley with 17 treatment rooms, a float tank, outdoor mineral spas and couples' treatments; day passes and walk-ins

Atlanta, Georgia

Hotel spa inside the Four Seasons Atlanta in Midtown, open to guests 16 and up for massages, facials and a heated saline pool with sauna and steam room.

Houston, Texas

A Four Seasons hotel spa in downtown Houston with three treatment rooms, a couples' suite and rooftop pool access, open to day-pass guests.

Milan, Lombardy

A luxury hotel spa inside Four Seasons Hotel Milano with a 14-metre pool under a vaulted ceiling, sauna, gym and private suites for couples' treatments.

Seattle, Washington

Hotel spa in downtown Seattle for Four Seasons guests, with a Himalayan salt wall, steam rooms and a six-treatment adults-only menu.

Washington, D.C., District of Columbia

Hotel spa at Four Seasons Washington, DC with a private contrast therapy room, pool, and an adults-only, couples-friendly treatment menu.

Orlando, Florida

Adults-only resort spa at Four Seasons Orlando, open daily 9am-8pm, with 12 treatments, couples' suites and access to a 21+ pool for guests booking a 50-minute

Santa Fe, New Mexico

A hotel-guests-only resort spa in Santa Fe with 15 treatment rooms, private soaking courtyards, saunas and steam rooms, built around Southwest-inspired rituals.

Vail, Colorado

A hotel spa at Four Seasons Vail with sauna, steam room, whirlpool and ten treatments, open to resort guests only, no day passes.

Washington, D.C., District of Columbia

Hotel spa near the White House offering massages, facials, body treatments and nails, with day passes and memberships open to non-guests.

Boston, Massachusetts

A luxury hotel spa in Boston's Back Bay with a Crystal Steam Room, Vitality Pool and private couples suites, open to adults 18 and over.

Miami, Florida

Hotel spa at The Ritz-Carlton Key Biscayne, Miami, with treatment suites, sauna, steam room and whirlpool, open to hotel guests 18 and up by appointment.

Galway, Connacht

Adults-only hotel spa in Galway with a thermal suite, hydro pool and sauna; day pass runs about €50 and reservations are required.

Chicago, Illinois

A hotel spa on Trump Chicago's mezzanine level offering day passes, 22 treatments, a heated pool, steam room, sauna and fitness club; minimum age 16.

Las Vegas, Nevada

A two-floor hotel spa inside Vdara with steam room, sauna, whirlpool and lounge, open only to Vdara and ARIA guests 18 and older, closed Tuesdays.

Calistoga, California

A 20-treatment hotel day spa in Santa Rosa with an indoor caldarium plunge pool, eucalyptus steam rooms, and walk-in or reserved day passes for adults 18+.

Miami, Florida

Adults-only hotel spa on Belle Isle near South Beach with a hammam, sauna, ice room, infinity pool and a day pass option for non-guests.

Philadelphia, Pennsylvania

Hotel spa in Center City Philadelphia with a heated indoor saltwater pool, fitness center and day-pass access for non-guests.

Brussels

Hotel spa on the 25th floor of The Hotel Brussels, with city views, sauna, steam room, salt sauna and a Technogym fitness floor.