Rodin referred to this jewel of European Gothic art as the "Acropolis of France". The cathedral is renowned the world over for its architectural unity, the beauty of its two lofty spires (106m and 115m) and statue-columns, the splendour of its sculpted doorways and its extraordinary 12C and 13C stained-glass windows, considered the most important collection found anywhere in France. For the past 800 years its vast ambulatory and huge transept have provided a focal point for pilgrims.