The current cathedral, mostly constructed between 1194 and 1220, is the last of at least five which have occupied the site since the town became a bishopric in the 4th century. It is in the Gothic and Romanesque styles. It is designated a World Heritage Site by UNESCO, which calls it "the high point of French Gothic art" and a "masterpiece". The cathedral has been well preserved. The majority of the original stained glass windows survived intact, while the architecture has seen only minor changes since the early 13th century. The building's exterior is dominated by heavy flying buttresses which allowed the architects to increase the window size significantly, while the west end is dominated by two contrasting spires, a 349 ft plain pyramid completed around 1160 and a 377 ft early 16th-century Flamboyant spire on top of an older tower. Equally notable are the three great façades, each adorned with hundreds of sculpted figures illustrating key theological themes and narratives.