Gates to the Underworld in Hierapolis, Phrygia

The journal Archeological and Anthropological Sciences has published an article about measurements of carbon dioxide at a site referred to by ancient historians and scholars as the Ploutonion, gates to the underworld.

Its abstract is here.

Are any faeries of established sagas interested in taking over the place?

Cheers

I think Guinea the Fetid was big on places like this.