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 105-metre (349 ft) plain pyramid completed around 1160 and the 113-metre (377 ft) Flamboyant (late Gothic) spire on top of an older tower. Its three great façades are adorned with hundreds of sculpted figures illustrating key theological themes and narratives.

Since at least the 12th century the cathedral