In 1858, after a lengthy and heated debate, work began on the Palmerston fortifications, a project that turned Portsmouth into one of the most strongly defended places in the world. Fort Brockhurst is one of two of the great bulwarks then built which are open to the public, offering the atmosphere of a medieval fortress with its drawbridge over a water-filled moat surrounding the castle. The keep is a circular building and beyond is a large parade ground surrounded by ramparts, where cannons were placed to command the local approaches to Portsmouth Harbour in the event of invasion. Building took place during several years of panic after the Crimean War when the French fleet modernised more quickly than our own. Over the years their facilities and accommodation were put to a variety of uses including the reception of soldiers returning from World War I. Suggested paranormal residents during the Fort's 150 year history have included a whistling Sergeant-Major, while the old Sergeant's mess is described as an intimidating area where visitors are reluctant to walk alone. Reports of ghostly footsteps and strange banging sounds have come from the Keep, while there is also said to be the spirit of a former prisoner, or possibly a prison guard. An area which was bombed during WWII, which is still rubble today, is also said to house spirits.