Under the pavilion is an undercroft or vaulted cellar. The four easternmost bays stood over an undercroft which forms part of the present crypt. Beneath the church is a large undercroft, built of brick and groin vaulted. For example, Crace decorated and gilded the ceiling of the Chapel of St. Mary Undercroft. Hague married Ffion Jenkins at the Chapel of St Mary Undercroft on 19 December 1997. In the 1980s the library expanded into the 12th century undercroft below the chapel. Its vaulted undercroft is no longer standing. A Mediaeval undercroft, human bones and parts of a coffin were also uncovered. It is a two-storeyed structure with the main chamber raised on an undercroft. The Pyx Chamber formed the undercroft of the monks' dormitory. It is a timber-framed octagonal building with an upper floor raised above an open undercroft. The Metrolink tram line passes under the station through the undercroft. Underneath the Hall is the college bar, located in an 11th-century undercroft. Beneath the Dutch House is the undercroft of a 16th-century building. The 14th-century Great Undercroft still survives, some long by wide, divided into 13 bays.