It's unclear who flushed the tunnels down there in the first place, but the middle son has a guilty look on his face.
The underground rooms and corridors were packed with treasures dating back thousands of years, including Roman artifacts, artwork left by the Knights Templar, a Messapian tomb, and a Jesuit ring that contained 33 diamonds. They also ... hold up, a stodgy Italian man trying to fix the plumbing finds himself transported to a vast land filled with riches?! Are we sure this isn't a Super Mario Bros. reboot?
"That's where the giant turtle started spitting fire at me. We're tennis buddies now."
Faggiano initially kept his little excavation project a secret from his wife, thinking she might object to the whole "lowering their 12-year-old son into unreachable spaces with a rope" part. Eventually, the massive amounts of debris he was hauling away in the family car became too obvious, and the authorities got involved. This means that the family unfortunately couldn't keep most of the treasure to themselves, due to a technicality called "the Italian government calls dibs."