Notre-Dame de Paris is a medieval Catholic cathedral on the Île de la Cité in the fourth arrondissement of Paris, France. The cathedral is widely considered to be one of the finest examples of French Gothic architecture, and it’s among the largest and most well-known church buildings in the world. The naturalism of its sculptures and stained glass serve to contrast it with earlier Romanesque architecture. The cathedral treasury contains a reliquary, which houses some of Catholicism’s most important relics, including the purported Crown of Thorns, a fragment of the True Cross, and one of the Holy Nails.
Notre-Dame de Paris was among the first buildings in the world to use the flying buttress. The building was not originally designed to include the flying buttresses around the choir and nave but after the construction began, the thinner walls grew ever higher and stress fractures began to occur as the walls pushed outward. In response, the cathedral’s architects built supports around the outside walls, and later additions continued the pattern. The total surface area is 5,500 m² .
Many small individually crafted statues were placed around the outside to serve as column supports and water spouts. Among these are the famous gargoyles, designed for water run-off, and chimeras. The statues were originally colored as was most of the exterior., but the paint has worn off. The cathedral was essentially complete by 1345. The cathedral has a narrow climb of 387 steps at the top of several spiral staircases; along the climb it is possible to view its most famous bell and its gargoyles in close quarters, as well as having a spectacular view across Paris when reaching the top.
The most significant change in design came in the mid 13th century, when the transepts were remodeled in the latest Rayonnant style; in the late 1240s Jean de Chelles added a gabled portal to the north transept topped off by a spectacular rose window.