It all started last week when we decided to get in on the Monuments in May 2012 here in Naples. We took a guided tour of the Agnano Thermal Baths and Grotto of the Dog organized by the Neapolitan Archaeological Group. That set off a planet-wide (really!) debate involving NUg, Prof. Jeff Matthews (from Naples) and the tireless and curious Larry M. Ray (from Gulfport, Miss. and New Orleans in the US).
The impetus came from Jeff and Larry when they found out that the Agnano basin, until just a few years ago, contained a lake fed by 75 thermal springs that to this day continue to gush up at various points in the valley.
Both Jeff and Larry were very familiar with Agnano since for decades the area was the seat of a US Navy base on via Scarfoglio, home to US citizens who for various reasons were in Naples. They both also knew of the famous horse track in the Agnano basin (still active today), of the thermal springs used in inhalation treatments of a variety of respiratory ailments, and of the mud baths for skin and bone conditions. What they didn't know about was the lake, there until 1871, the year in which it was emptied as part of a general project of land reclamation and water management in the entire area.
Anyway, Larry found a few clues during his frequent consultations of Google Maps, always on the search for hidden nooks and crannies in the land of Parthenope! He noticed a series of straight lines converging spoke-like on a circular structure in the southern part of the Agnano crater. Like an Italic Nazca, the design on the landscape looked like a solar disc, but only visible from above.
He recalled his initial observation of the pattern when he heard of our plan to visit the area, and he mentioned the satellite images to me. I told him right off that he had seen the pattern of canals that were part of the reclamation project and put to rest any fantasies of Nazca-lines.
The discussion went back and forth in a kind of game with each one of us trying to show off how much he knew about the area. At that point, when I saw how interested Larry was in what I was saying, I decided to hit him with everything I had—the big one. It would knock his eyes right out of their sockets!
In my best detective fiction, slow and suspenseful delivery, I said: "Lorè...(the Neapolitan term of endearment for Larry)...I'm going to let you in on something that you couldn't have imagined in your wildest dreams." (Here I paused long enough to watch his expression change on my Skpe screen; then I went on in that deliberate slow cadence of one who is about to reveal the secret code for a missile launch)..."Did you know that the lake was emptied in a just a few days? It was just like emptying a giant bath-tub. They simply pulled the plug."
I think Larry must have thought I was pulling his leg, but my insistence on that point stirred his curiosity. He was determined to get to the bottom of what I was talking about.
I dropped my voice-of-mystery act and simply told him the surprising facts of the matter. A tunnel had been dug in the latter half of the 1800s to join the lake bottom with the Bagnoli coast. It was then a simple matter of dropping the final partition in the tunnel and the entire contents were emptied in hours. I wound up with: "I'd really like to know the precise point on the coast where that tunnel comes out."
Larry wasn't quite sure how to take the story. He was perhaps a bit suspicious that I was having a little joke at his expense—that, however, was mixed with a desire to find out what was really going on in what seemed to be yet another tale of Naples Underground. Neapolitans, descended from the mythical Cimmerians, seemed to have no equal when it came to digging beneath the earth.
Finally, he decided I was telling the truth, He signed off with a look of one who is thinking, "OK. You won that round...but tomorrow...I'll show you what I can do."
To be honest, I don't know how he manages to piece together all of this seemingly unconnected information from the internet. Let's just say that he is very good at it.
The next morning, among my morning batch of emails that had come in during the night, there was one from the States with the clear subject line: "The Mystery of Lake Averno."
In a few words and a series of images, they solved the mystery of the tunnel. It existed, was documented and now we know where it comes out.
The first is an original old map that traces the path of the tunnel; then, superimposed, a tracing of the tunnel on a modern map of the area; finally, a series of Google satellite shots narrowing down to the structure on the coast, itself, that today still takes the overflow from the 75 springs in the Agnano basin.
Translated by Jeff Matthews
This evening we received an email that, with extreme precision, moves us about 82 meters west/north-west for the exact spot on the coast where the drainage tunnel from the old Lake Averno enters the sea. Larry's calculation was off by a bit since he was working from an old and incomplete chart from 8993.1 km away near New Orleans. He was close, but he doesn't win the prize. "Close but no cigar," as they say!
Below find two images: the first shows the distance between the two points—one, the discharge drain from Agnano and, two, the conduit that carries the rain run-off from Pianura along via Cinthia; the second image correctly shows the location of the Agnano drain.