The archeological crypt at Notre Dame
Métro: Cité | Website
The archeological crypt at Notre Dame — aka La crypte archéologique du parvis Notre-Dame — is a small subterranean museum that lets you explore several layers of Parisian history just as they were uncovered by archeologists on the Île de la Cité.
Paris as we know it began on this little island, and a good two thousand years of history lie below its streets. As you explore the crypt you can see layer upon layer of bricks and paving stones from the various eras of Parisian history, all the way back to the Gallo-Roman era and the Middle Ages, and all the way up through the 18th and 19th centuries. It's a fascinating walk through a couple millenia of Western civilization.
I added my photo of the crypt's entrance here because it's really easy to miss if you're not looking for it. That big pretty cathedral is pretty distracting! Anyway, as you can see, the entrance is a stairway leading underground, way out on the far side of the parvis (open square) in front of Notre Dame.
Related junk from Cool Stuff in Paris:
More skulls than you can shake a femur at.Le Musée des Égouts de Paris
The Paris Sewer Museum.An unfinished statue of the Virgin Mary
Buried for eight centuries.Les Arènes de Lutece
The site of an ancient Roman arena in Paris!