Bull Sand Fort, off the coast of Lincolnshire in northern England, was built to house 200 soldiers and is only accessible by boat or helicopter. The fort is now listed with property firm Savills and is due to go up for auction on July 19. “It will require an imaginative buyer with a project in mind, but suggestions for future uses so far include a high-end hotel, restaurant, Airbnb, grand design style personal residence, retreat and a tourist attraction,” said Steven Morish of Savills. The fort needs some love in the form of renovation, Morish says, but has potential for alternative uses if allowed. However, it is Grade II listed, meaning any development plans must first be approved.