Housesteads is the most complete Roman fort in Britain. Set where Hadrian's Wall climbs to the top of a dramatic escarpment.
It was built within a decade of AD 122, when work on the Wall began, and was garrisoned by an 800-strong infantry regiment until the end of the 4th century. Excavations have revealed major buildings, defences and the civilian settlement outside its walls.
One of the most famous features of Housesteads is the Roman toilet block, seen here.