The Cathedral of Notre-Dame de Paris, a masterpiece of Gothic architecture, is the most visited monument in France. It was built in the Middle Ages, at the far end of the Île de la Cité. Work started in the 13th century and finished in the 15th century. Badly damaged during the French Revolution, the cathedral was restored in the 19th century by the architect Viollet-le-Duc. Its many visitors come to admire its stained glass and rose windows, the towers, the steeple and the gargoyles. They can also discover the Notre-Dame treasury and have a go at climbing the towers to enjoy a panoramic view of Paris. In 2013, Notre-Dame is celebrated its 850th anniversary. For this occasion, many events were organized and the cathedral renewed its bells with the arrival of eight new bells as well as a new great bell. Road distances from Paris in France are calculated from point 0 on the cathedral forecourt.