Is this the entrance to Hades?
We can see some of the massive Greek stone blocks which M. W. Frederiksen of Worcester College, Oxford, dated to probably the 6th or 5th century BC, hundreds of years before any Roman set foot here and related to one of the earliest Greek settlements in Italy, about 4 kms (2 ½ miles) away at Kyme, today called Cuma. The dark shape of the Grotto entrance faces us and to its left another passage into the cliff, which is currently blocked a short distance into the hillside. In the left picture above we are looking along a Roman wall which once divided the Greek Temple from the building adjacent to it.
How the main tunnel was accessed originally, the Great Antrum as Doc Paget termed it, is unknown. There are hints that there may once have been a stairway down, but only a proper investigation will prove this. Doc Paget may be right and the adjacent entrance was used, which he termed the Original Entrance. I am inclined to think perhaps the Tholos passage may have been the original entrance. They may all have been used for separate purposes. We don’t yet know.
The tunnel underneath cannot have been a water channel because it slopes down into the hill, its lowest point being an estimated 20 metres (65 ½ feet) lower – just three metres (10 feet) or so above sea level.
Below the Greek Temple
Once we have dropped below the surface buildings which sit on a terrace 23 metres (75 ½ feet) above sea level, we are in a narrow trench about 1 metre wide (3 feet 3⅜ inches) on a bearing of 275º. Where the tunnel enters the hillside it narrows to about 0.55 of a metre (21 inches) – shoulder width – and the tunnel changes angle to due west or 270º.
The tunnel continues into the volcanic crater wall in a perfectly straight line for 124.5 metres (408 ½ feet), maintaining its narrow width and a height of about 1.8 metres. There are centuries of crystalline deposits on the floor, so the height is now reduced somewhat from the original.
The trench forming the start of the Great Antrum was once covered over and situated under the floor of the Greek Temple. When the site was cleared and the débris removed, it left the deep trench open to the sky that we see today.
The trench roof
It seems likely the same arched tile system used within the first section of tunnel – see sidebar – extended outwards from the interior. This would have put the floor level of the Greek Temple, at least in Roman times, at a similar height to the Grotto floor above it.
Vesuvius at the equinoxes
If we start our descent at one of the equinoxes, around 20 March or 22 September, when the days and nights are equal lengths, looking back due east we will see the sun rising behind Vesuvius.
You are here
This view shows the supporting structure for the Grotto, which lies above here. Angled tiles have been notched so that they intersect and lean on each other. The concrete base of the Grotto floor above has been set on top of the tiles.
This is a picture showing the view looking up into the Great Antrum. Could this be, as Doc Paget suggested, the entrance to the underworld of mythology and legend, said to be located in this area?
Behind the cliff
Our story continues with what lies behind the cliff.