The Notre Dame cathedral in Paris is one of the finest examples of French Gothic architecture in Europe (thank you high school art history class). It is a must see when visiting, even if it is just walking around the outside. I’m not a big architecture expertise or a big historical church visitor, but it doesn’t take much knowledge to know this is gorgeous. I couldn’t imagine constructing Notre Dame now, let alone in 1163. The thin walls, which became a popular style in French Gothic architecture, lead to many stress fractures during the construction. The addition of flying buttresses, which can be seen on the back side of the cathedral, provided the additional support needed to maintain this structure. Eventually they became popular and somewhat decorative. Flying buttresses can now be seen in many designs of other buildings throughout Europe.