A defensive fortification in northern Britain. It was built 122–26 ad after a visit to Britain by Emperor Hadrian. It is 117 km (73 miles) long, a stone barricade with a turf section in the west. Large fortress bases, mile-castles, and signal towers marked its length. A road ran along it to the south and defensive ditches accompanied it on both sides. The wall was damaged several times by the Picts and was finally abandoned in 383, but long stretches of the wall still stand.