There is a fascinating report by Duncan Kennedy on the BBC News website this morning about underground caves and tunnels in Naples. Watch the video here, it's well worth it.
There's one ancient cave that was used as an air-raid shelter during WW2 and looks like it might have once been a mithraeum (?). Does anyone know anything about this? Any bibliography you could share or contact details of the people working in the caves? I would love to know more about what's happening here.