An interpretative centre sits over what was formerly the eastern curtain wall. The centre, described as the ‘Learning Wall’, bridges an archeological dig of the former wall and bastion, which can be viewed in the building’s undercroft. The building is basically a ‘blackbox’ for exhibition space but the exterior surface is broken up by using an external structure in steel. The ‘city’ side of the building incorporates parts of the original stone walls while the castle courtyard façade is more uncompromisingly modern in appearance. Overall, the architects bypassed the easy pastiche option and produced a building which sits easily into the medieval fabric of the castle.