The Wall: Rome's Greatest FrontierHadrian's Wall is the largest, most spectacular and one of the most enigmatic historical monument in Britain. Nothing else approaches its vast scale: a land wall running 73 miles from east to west and a sea wall stretching at least 26 miles down the Cumbrian coast. Many of its forts are as large as Britain's most formidable medieval castles, and the wide ditch dug to the south of the Wall, the vallum, is larger than any surviving prehistoric