Spitbank Fort

One of a series of sea forts that were royally commissioned in 1878 to protect Portsmouth harbor from a French attack that never came, Spitbank Fort became "redundant" and sat unused until 2012, when the Clarenco Group converted it into a luxury hotel. Many of the fort’s original features have been kept intact. In addition to the exposed brick walls, gun ports were transformed into bedroom windows with sea views, and gunpowder rooms became cozy lounges.While the brutal-looking granite exterior may not appeal to everyone, the interior is chic and pretty, and is so glam that when guests first enter through the heavy wooden doors they are handed flutes of Laurent Perrier Champagne. The original distressed-brick walls and riveted ceilings have been retained, and old British board games and posters from World War II decorate the lounge.Each windowsill, wall and shelf is packed with nautical paraphernalia, from telescopes and bells to crazier items like two vast missiles lying hidden under benches. The top deck has a hot tub, sauna, a fire pit, and a lounge bar, sunbathing decks, and a lighthouse with views past the coastline toward the Isle of Wight. Below deck, the historic storerooms have been converted into a labyrinth of rooms -- a small gym with weights, a game room, a wine cellar, and a shisha den. Since leaving the hotel is not that easy, guests are all in it together here, and friends are made quickly. Relaxed exclusivity would best describe the vibe. Spitbank Fort can be booked for private parties, weddings, and corporate events and conventions. 

Located one mile off Porstmouth Harbor, Spitbank Fort occupies its own island. Naval enthusiasts and history buffs can visit the restored battle ships HMS Victory and HMS Warrior, as well as the remains of the Mary Rose, all of which reside at Portsmouth's historic dockyard. Otherwise, guests typically come here to stay put, as they can only leave the fort only by private boats -- a 30-minute ride --  which run only three times a day. 

The quaint rooms in this sprawling old fort are full of nooks and crannies, with plenty of starfish and shells rounding out the nautical theme. Each room is vast and individually designed, with gun ports that have been transformed into windows that look out onto the water, and curvy, undulating ceilings. All rooms come with flat-screen TVs and tea- and coffee-making facilities. Some bathrooms have double sinks and deep-soaking, free-standing tubs. The Admiral Churchill Suite has an outlandish silver bed, and a wild-looking white leather Chesterfield with diamante studs -- which is definitely on the bling side of things. Full-size telescopes to watch the night skies are extra room perks.

Spitbank Fort has been classified as a Scheduled Ancient Monument, which means it is a historic building that is protected against unauthorized change. The hotel offers snug blankets and hot chocolate by the fire pit during Sunday stays, and a rooftop hot tub with picturesque views of the sea. Fishing and kite flying are available as activities. The restaurant  serves top-quality food, and there's also a wine cellar on-site. There's also three bars and free Wi-Fi, and a restored lighthouse with views that stretch as far as the Isle of Wight on a clear day.