The iconic roof of Notre Dame that has partially burnt down in the ravaging fire was made up of some oldest surviving timber frames. During the 12th-century, about 52-acres of trees were cut to build the structure. Each beam of the structure was designed from a particular tree! It is also a reason why its woodwork lattice was commonly referred to as "the Forest".
During the French Revolution in 1793, 28 statues of erstwhile kings kept here were taken down and beheaded by the people. The mangled heap of stones was ordered by the Minister of the Interior to be used for some other construction purpose. In 1977, while working on the basement of the French Bank of Foreign Trade, 21 heads out of 28 were discovered by workers. They have since been kept for viewing by people at the Musee de Cluny that is located very close to the cathedral.
At a glance, the towers of the cathedral may seem to be like twins but on closer inspection, one can easily find out that the north tower is slightly bigger in size than the southern one. The cathedral was not designed by any one person. Rather, it was built gradually over a period of time and reflects the leadership and architectural trends of that period. It is more of a collection of thoughts that leaders displayed at the time.