The most striking feature of St Mary's is the 27m-high crossing tower, with its profusion of gargoyles and pinnacles, copied from the one in Wells Cathedral. In the 16C, side aisles were added to the 15C Perpendicular Gothic building. Note the fan vaulting in the transept crossing, as well as Wadham Chapel (left side of the transept), built in 1452 to house the tombs of Sir William Wadham and Nicholas Wadham, founder of Wadham College in Oxford.