Located at Durham, England
The Cathedral at Durham is the first architectural structure to utilize a ribbed groin vault over a three story space. The side aisles utilize this vaulting method, and their bays are almost square; however, the nave bays expand across two side aisle bays to form a double-x within its ceiling. Massive transverse arches are supported by great, compound piers that are considerably thicker than the piers in-between. Interestingly, the transverse arch at the crossing is round; however, those more west (built later) are slightly pointed, indicating experimentation for more efficiency and stability as time progressed and technology improved. At the springing of the ribs on the gallery level are massive buttresses, which themselves are buttressed by the cathedral’s exterior walls.