Grotte di Pilato

Useful Information

Location:	Via Madonna, 04027 Ponza LT. (40.8961181, 12.9710930)
Open:	no restrictions. [2025]
Fee:	free. [2025]
Classification:	Enigmatic Cavern
Light:	Incandescent
Dimension:
Guided tours:	self guided
Photography:	allowed
Accessibility:	no
Bibliography:
Address:	Grotte di Pilato, Via Madonna, 04027 Ponza LT, Tel: +39-0. Vivi Ponza, Via de Luca Sindaco, 113, 04027 Ponza LT, E-mail:
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

1997	Roman marble statue and some oil lamps from the Roman era found.

Description

The Grotte di Pilato are mysterious caves in the cliff on the eastern side of Ponza Harbour. The Isola di Ponza is one of the Pontine Islands, located west of Ischia, and belonging to Lazio. It is reached by ferry from Anzio, Terracina, and Ischia. The harbour is a cove with a peninsula protruding to the east, which is called Punta della Madonna. The city extends partly on the peninsula, on the tip are a cemetery, a botanical garden, a lighthouse and a church. If you visit this peninsula, you will miss the main sight though, the numerous sea caves at the vertical cliffs. In other words, the address Via Madonna given by Google is actually wrong. The only way to visit them is by boat from the harbour. There are regular boat trips offered to tourists.

On the first glimpse a sea cave, while always nice to visit, is not really exceptional. Those caves here are not exceptionally big or spectacular. But at the second glimpse you can see the strange form. Those caves have vertical walls, a rectangular floor and a barrel vault. They were obviously dug artificially. Even underwater the walls are straight, as well as the floor. How old they are and for what purpose they were dug is quite enigmatic though, that’s why we classified them as Subterranea Enigmatic Cavern.

The most likely theory is that those caves were dug into the island’s volcanic rock around the 1st century, during Roman times. They form five basins connected to each other via underwater passages. They were fish farms where moray eels were bred, which is why they are also called Murenai. The main pool has five openings, in Roman times each was closed by a sluice gate. They allowed changing the water and transferring the fish from one tank to another. Above, were today the cemetery is located, was a beautiful Roman villa built by the emperor Augustus.

The island is of volcanic origin, and the rocks are volcanic tuff. Actually this fact makes it quite unlikely that the cave were dug at this lever, or in other words, the caves may have been dug above the sea level. Volcanic activity causes uplift of the surface due to magma flowing into a magma chamber below and due to increasing pressure. If the volcanic activity decreases, the surface goes down again. It is actually extremely unlikely that the sea level was at the same level at the cave two millennia ago. Such downlift is well known from nearby Capri Island. If the ancient sea level is known here, it is not published in order to keep the eel farm legend up.

The caves are finely chiseled and embellished with decorations carved into the tuff. There were also some findings in recent years which led to the assumption of a religious use of the caves. Niches in the caves housed statues of pagan deities and were lit by skylights which are still visible. In the middle of the back wall of the main cave there was a white marble statue probably depicting Apollo or Dionysus. It was discovered together with a small tuff altar and some terracotta lamps in 1997. The name of the caves is derived from an old legend, as far as we know there are no historic facts that it actually happened. Historians disagree on the matter.

The name of the cave is linked to that of Pilate who was a young scion of a noble Roman family. He had been sent to Ponza to quell a revolt, but more likely to keep him away from trouble and the reckless life of the city. Unexpectedly Pilate succeeded in the task assigned to him, and the Senate promoted him. They assigned him the rank of Governor and the title of Pontius, and then sent him to Palestine to subdue the rebellious Jews. He is today well known as Pontius Pilate, the governor of Judaea, who presided over the trial of Jesus.

The peninsula has more caves, on the southern side. There is the Grotta di Ulisse and another one which seems to have no name. Those caves are of natural origin, formed by the erosion by the waves. All the caves are visited on the boat tours.