Burgh Castle - Roman Fortification

Burgh Castle, possibly the Roman fort of Gariannonum, is one of nine Saxon Shore forts built in the late 3rd century AD (c. 260-280) to defend against seaborne raiders along Britain's east and south coasts. Located overlooking the River Waveney estuary in Norfolk, the roughly rectangular fort covered about 2.4 hectares with walls 3.5 metres wide at the base, rising to 4.5 metres high, faced with alternating bands of cut flint and tile. Projecting bastions once supported catapults called ballistae. Three of the four original walls survive nearly to full height, making it one of Britain's best-preserved Roman monuments, though the west wall has long since collapsed into the marshes.