Hadrian's Wall was built to set the northwestern limits of Roman Imperial expansion and "to separate the barbarians from Romans". The frontier system, with its supply bases, garrison forts, signal stations and network of roads, is the most extensive, complex and best preserved of the Roman Imperial boundaries, the most distinctive feature being the curtain wall, which runs for 117 km from Wallsend to the Solway.
Coastal watchtowers extended the defensive system a further 42 km along the Cumbrian coast to Whitehaven. The remains, dating from AD 122 and covering almost all of the period of Roman occupation of Britain, have been extensively excavated and laid-out for public display. The World Heritage Site contains 11 museums, which together provide a unique insight into life on the Wall for both the garrisons, drawn from all parts of the Empire, and the native population.