The Île-de-la-Cité on which Notre-Dame de Paris now stands was once a Gallo-Roman city known as Lutetia. The cathedral has been built right over remnants of a temple. Around 1710, pieces of a sculpted altar dedicated to Jupiter and other deities were discovered during an excavation under the choir.
At first glance, Notre-Dame’s two towers appear like identical twins. Closer examination reveals that the north tower is, in fact, a bit bigger than the south.
As with all the elements of the cathedral, they were built over time, and reflect how the cathedral is more of a collage of architectural trends and leadership than the culmination of one person’s vision.