Deyrolle: The Strangest Shop in All of Paris. "Paris has many unusual shops, but one of the most unusual has to be Deyrolle."
The catacombs of Paris are an immense maze of tunnels dug under the city. In 1786, all the bodies from Cimetiere des Innocents were exhumed and moved into the tunnels. A sign above the door reads: Stop! Here is the empire of the dead... For a significantly less creepy (and infinitely cool) city under the city experience, check out the Seattle Underground tour.