Portsmouth is one of the most densely populated cities in Southern England, and is unusual as most of its built-up area occupies Portsea Island, linked to the mainland by road and rail bridges. Although there is a Roman fort at nearby Portchester, occupied later by the Saxons and Normans, there was no settlement on the site of Portsmouth at the time of the 1086 Domesday Book. The town developed in medieval times and received its first charter in 1194 from King Richard I; soon afterwards it became a major naval base. It has the world’s oldest dry dock, and is home to several famous ships, including HMS Victory, HMS Warrior and the Mary Rose, raised from the Solent in 1982. Portsmouth remains an important naval base and is home to a large proportion of the British service fleet. The waterfront area is now dominated by the Spinnaker Tower, 560 feet high, the United Kingdom’s tallest building outside London. Other things to see in the city include the house where Charles Dickens was born, and the City Museum, which contains a permanent exhibition devoted to another famous writer, Sir Arthur Conan Doyle, who lived in the town.