What was once a 19th-century military fortress on the southern flank of the bay of Palma has been converted into one of Mallorca's—and arguably Europe's—most distinctive hotels. On a rocky outcrop some 25 minutes from Palma, in a protected nature reserve, the sprawling complex of redoubts and ramps and stone-walled vaulted armories covers some 70 acres; guests can get from one part to another in electric carts. The decor, courtesy of owner-architect Antonio Obrador, pays homage to the property's past with stylized bullets for door handles and lamps made of old cartridge cases, for instance, as well as touches of Morocco and Turkey: carpets, divans, wall hangings. The suites have huge bathrooms, locally sourced upholstery and textiles, including soft curtains in earth tones and specially commissioned carpets, and individual rooftop terraces. The two restaurants are open to the public; the more informal waterside Sea Club, with its own boat landing, is perfect for romantic candlelit dinners. Take your ease by the saltwater infinity pool; there's a push-bell on the table by your deck chair, to summon your drink.