Casa Madrona looks more like a Victorian mansion than a spa or hotel—and, in fact, it once was. Looming large on Sausalito's hillside, overlooking ships sailing in and out of harbor, the building dates back to 1885, when it was constructed for William Barrett, then secretary-treasurer for the San Francisco Gas and Electric Company. It would take more than a century, plus a multi-million dollar renovation that added cottages and new buildings, to transform Casa Madrona into what it is today: a contemporary escape.

The original mansion—now listed on the National Register of Historic Places—still houses guest rooms that overlook San Francisco's shoreline and whatever giant monster is currently terrorizing it. Larger parties can even rent out the hotel's crown jewel: the 5,000-square-foot Alexandrite Suite. But overnight stays are hardly a requirement for visiting, thanks to the full-service spa.

Here, the treatment menu splits luxury into three categories—body therapy, massage therapy, and skincare therapy— and draws inspiration from nature. The Sea to Shore massage, for instance, sees therapists incorporate aromas of rosemary, cypress, and wild ginger, as well as a signature blend of essential oils, to illicit total relaxation. After a treatment, visitors can cap off their evening at the hotel-adjacent Poggio Trattoria, where chefs cook traditional Italian cuisine.