arcade pillars to support the vaults. The pillars of the arcade, consisting of bundled columns, also have decoration; sculpted grapevines and other vegetal designs, from about 1245. The four-part rib vaults of the nave vaults are exceptionally high; between 41.2 and 42.6 meters, exceeded in height only by those of Beauvais Cathedral (48 meters), matching those of Amiens Cathedral (42.3. meters), and taller than those of Reims Cathedral (38 meters). The collateral aisles on either side of the nave are not nearly as high; just 13.3 meters, but they also have walls largely filled with stained glass. Transept and choir The Transept and choir were built later than the nave, between 1487 and 1520, with elaborate decoration in the flamboyant style of the late Gothic in the tracery of the windows and the pillars. Nonetheless, the builders respected the elevations and distribution of space on the walls established in the nave at the end of the 13th century. The high windows of the nave were the model for the high windows in the transept and the choir. Parts of the north transept also serve an important structural purpose; the section of the transept where it meets the nave, made about 1300, also serves a buttress for the arches of the nave where they meet the transept. Each level of the transept also has narrow coursières, or passageways, built in the wall on the interior and exterior of the transept. The vaults of the transept meet the vaults of the nave and choir at the central crossing. The transept is 46.80 metres (153.5 ft) high and 16.34 metres (53.6 ft) wide. The vault in the center of the crossing has additional decorative lierne and tiercon ribs, which form a star, and a large keystone, 1.7 meters high and 3.7 meters across, at the meeting point. The choir of a cathedral, where the clergy traditionally worships, is usually long, but because of the unusual topography under the cathedral, the choir in Metz is relatively short, and raised up by twelve steps from the transept. The modern liturgical furniture in the choir was created by the Swiss-born French artist Mattia Bonetti between 2004 and 2006. It includes an altar, Ambon or tribune, and cathedre, or bishop's chair. They are made of bronze, marble and oak, with a motif of reeds gently blowing in the wind, against a dark background. The Altar of Notre