Calistoga Ranch, California
This 50-room resort, tucked away in a private canyon in Napa, takes full advantage of its forest surroundings. Each bathroom has a wooden deck with an outdoor shower garden built—literally—around existing trees (some of which make it inside the wood walls). You'll also spot vines crawling up the artful metalwork and fresh rosemary, lavender and eucalyptus bouquets by the copper rain showers, hung by staff as a form of natural aromatherapy. Prefer more of a hotel-room feel? Glass doors separate the showers from indoor bathrooms, whose natural palette (slate floors, rich mahogany fixtures, earthtone vases from nearby Calistoga Pottery) still blends perfectly into the setting.