Chartres is renowned for its iconic Cathédrale Notre-Dame, a masterpiece of French Gothic architecture and a designated UNESCO World Heritage Site. Constructed between 1194 and 1220, this cathedral stands on a site that has been sacred since the 4th century, replacing earlier buildings that were destroyed. It's celebrated for its stunning stained glass windows and the Sancta Camisa relic, believed to be the tunic worn by the Virgin Mary at Christ's birth. The cathedral's two contrasting spires and the three elaborately decorated façades are a testament to the ingenuity of medieval architecture.