Fodor's Expert Review Spa Solage

This 20,000-square-foot eco-conscious spa reinvented the traditional Calistoga mud-and-mineral-water regimen with the hour-long "Mudslide." The three-part treatment includes a mud body mask applied in a heated lounge, a soak in a thermal bath, and a power nap in a sound-vibration chair. The mud here, less gloppy than at other resorts, is a mix of clay, volcanic ash, and essential oils. Massage and other traditional services are available, along with hydration therapy, infrared saunas for exfoliation and relaxation, and wellness sessions.