Built with 4-m thick walls on the vaults of the Roman Temple of Claudius, its massive dimensions (46 m by 34 m) are one and a half times those of the White Tower in the Tower of London. It is now a museum housing one of the largest collections in Bri..

Only the skeleton remains of the 12C priory, yet it gives an idea of its size. Built, like the castle, of Roman brick, only the piers, west front (with the earliest circular windows in Britain) and the 37 m nave now remain.

The 3 m-thick Roman walls encircling the town centre are made of cemented stone between brick bonding courses. They are best viewed from Balkerne Hill , where Balkerne Gate, with arches and flanking towers, extends 9 m in front of the wall.