The Isle of Portland is a tied island, long by wide, in the English Channel. The southern tip, Portland Bill lies south of the resort of Weymouth, forming the southernmost point of the county of Dorset, England. A barrier beach called Chesil Beach joins Portland with mainland England. The A354 road passes down the Portland end of the beach and then over the Fleet Lagoon by bridge to the mainland. The population of Portland is 13,417. Portland is a central part of the Jurassic Coast, a World Heritage Site on the Dorset and east Devon coast, important for its geology and landforms. Portland stone, a limestone famous for its use in British and world architecture, including St Paul's Cathedral and the United Nations Headquarters, continues to be quarried here. Portland Harbour, in between Portland and Weymouth, is one of the largest man-made harbours in the world. The harbour was made by the building of stone breakwaters between 1848 and 1905. From its inception it was a Royal Navy base, and played prominent roles during the First and Second World Wars; ships of the Royal Navy and NATO countries worked up and exercised in its waters until 1995. The harbour is now a civilian port and popular recreation area, and was used for the 2012 Olympic Games. The name Portland is used for one of the British Sea Areas, and has been exported as the name of North American and Australian towns. History Portland has been inhabited since at least the Mesolithic period (the Middle Stone Age)—there is archaeological evidence of Mesolithic inhabitants at the Culverwell Mesolithic Site, near Portland Bill, and of habitation since then. The Romans occupied Portland, reputedly calling it Vindelis. Although the beginning of the Viking Age in England is dated to their raid in 793, when they destroyed the abbey on Lindisfarne, their first documented landing occurred in Portland four years earlier, in 789, as recorded in the Anglo-Saxon Chronicle. Three lost Viking ships from Hordaland (the district around Hardanger fjord in west Norway) landed at Portland Bill. The king's reeve tried to collect taxes from them, but they killed him and sailed on. A castle on the site of the present Rufus Castle, standing over Church Ope Cove, may have been built for William II of England (also known as William Rufus) soon after the conquest of England by his father William the Conqueror. None