was retired from royal service, decommissioned and relocated to Leith as a museum ship. HMNB Portsmouth is an operational Royal Navy base and is home to two-thirds of the UK's surface fleet. The base has long been nicknamed Pompey, a nickname it shares with the wider city of Portsmouth and Portsmouth Football Club. The naval base also contains the National Museum of the Royal Navy and Portsmouth Historic Dockyard; which has a collection of historic warships, including the Mary Rose, Lord Nelson's flagship, (the world's oldest naval ship still in commission), and , the Royal Navy's first ironclad warship. The former shore establishment has been redeveloped into a large retail outlet destination known as Gunwharf Quays which opened in 2001. Portsmouth is among the few British cities with two cathedrals: the Anglican Cathedral of St Thomas and the Roman Catholic Cathedral of St John the Evangelist. The waterfront and Portsmouth Harbour are dominated by the Spinnaker Tower, one of the United Kingdom's tallest structures at . Southsea is Portsmouth's seaside resort, which was named after Southsea Castle. Southsea has two piers; Clarence Pier amusement park and South Parade Pier. The world's only regular hovercraft service operates from Southsea Hoverport to Ryde on the Isle of Wight. Southsea Common is a large open-air public recreation space which serves as a venue for a wide variety of annual events. The city has several mainline railway stations that connect to London Victoria and London Waterloo amongst other lines in southern England. Portsmouth International Port is a commercial cruise ship and ferry port for international destinations. The port is the second busiest in the United Kingdom after Dover, handling around three million passengers a year. The city formerly had its own airport, Portsmouth Airport, until its closure in 1973. The University of Portsmouth enrols 23,000 students and is ranked among the world's best modern universities. Portsmouth is the birthplace of notable people such as author Charles Dickens, engineer Isambard Kingdom Brunel, former Prime Minister James Callaghan, actor Peter Sellers and author-journalist Christopher Hitchens. History Early history The Romans built Portus Adurni, a fort, at nearby Portchester in the late third century. The city's Old English Anglo-Saxon name, "Portesmuða", is derived from port (a haven) and muða (the mouth of a large river or estuary). In the Anglo-Saxon Chronicle, a warrior named Port and his two sons killed a noble Briton in Portsmouth in 501.