This 2019 episode notes that the Catacombs contain the bones of an estimated 6 to 7 million people, and explains that their history is really two interconnected stories of mines and human remains.

Behind the Scenes Minis: Piece of Work
17:48

E. Virgil Neal: Hypnotist, Fraudster, Tycoon, Part 2
41:22

E. Virgil Neal: Hypnotist, Fraudster, Tycoon - Part 1
35:28