age of smaller structures generally, which was associated with demographic decline, the Hundred Years' War, and with the thirteenth century. However, large-scale Gothic design continued, and the choir was rebuilt at the same height, albeit with more columns in the chevet and choir, converting the vaulting from quadripartite vaulting to sexpartite vaulting. The transept was built from 1500 to 1548. In 1573, the fall of the 153 m (502 feet) central tower stopped work again. The tower made the church the tallest structure in the world (1569–1573). Afterwards little structural addition was made. The choir has always been wholeheartedly admired, with Eugène Viollet-le-Duc calling the Beauvais choir "the Parthenon of French Gothic." It inspired the main administration building of Fermilab near Chicago, Illinois, which has been the world's leading high-energy physics laboratory since the 1960s. The building is now called Wilson Hall after Robert R. Wilson, its founding director and a sculptor who insisted on an uplifting aesthetic. Its façades, especially that on the south, exhibit all the richness of the late Gothic style. The carved wooden doors of both the north and the south portals are masterpieces, respectively, of Gothic and Renaissance workmanship. The church possesses an elaborate astronomical clock in neo-Gothic taste (1866) and tapestries of the 15th and 17th centuries, but its chief artistic treasures are stained glass windows of the 13th, 14th, and 16th centuries, the most beautiful of them from the hand of Renaissance artist Engrand Le Prince, a native of Beauvais. To him also is due some of the stained glass in St-Etienne, the second church of the town, and an interesting example of the transition stage between the Gothic and the Renaissance styles. During the Middle Ages, on January 14, the Feast of Asses was annually celebrated in Beauvais Cathedral, in commemoration of the Flight into Egypt. Structural condition In the race to build the tallest cathedral in the 13th century, the builders of Saint-Pierre de Beauvais pushed technology to its limits. Even though the structure was to be taller, the buttresses were made thinner in order to pass maximum light into the cathedral. In 1284, only twelve years after completion, part of the choir vault collapsed, along with a few flying buttresses. It is now believed that the collapse was caused by resonant vibrations due to high winds. The accompanying photograph shows lateral iron supports between the flying buttresses; it is not