[[Image:Hadrian's Wall.gif|thumb|At Milecastle 42, Cawfields.]]
[[File:Hadrian's Wall.jpg|thumb|150px200px|Near Housesteads in Northumberland.]]
'''Hadrian's Wall''', also called the "Roman Wall" or "Picts' Wall," was a [[border wall]] built by the Romans across [[Britain]] in the 2nd century AD to mark and defend their northern frontier from [[Picts|Pictish]] incursions (an alternative theory is that is was not primarily a defensive structure but a tax barrier). The [[Roman Emperor]] [[Hadrian]] visited Britain in AD 122, and the wall began construction around the time of his visit, and upon his orders.