The Archeological Crypt of Notre Dame Square showcases the origins of the city of Paris

On the far side of the parvis (the plaza in front of Notre Dame cathedral), there's an almost completely overlooked modern staircase leading down into archaeological excavations beneath Notre Dame's square that include bits of the original Celtic Parissi settlement and the ancient Roman city of Lutècethat took its place.

Not much here, really, but it's fascinating to see and fascinating to picture a small Celtic village on this island that grew to become the mighty city of Paris.