To the west of the peak of Evzona of Mount Hymettus, at an altitude of 810m, an imperceptible fissure measuring 0.40 x 0.70 cm leads to the deepest known cave in Attica. It was explored for the first time in 1948 by the E.O.S. and P.A.N. clubs, with a maximum recorded depth of -138m.

Then, it was explored by a team of the Hellenic Speleological Society (E.S.E.), which included it in its archive with registration number No. 19 and the same maximum depth.

In January 1993, members of the Hellenic Speleological Exploration Group (SP.EL.E.O.) carried out a new expedition, reaching for the first time a depth of -124m.

On November 03, 2005, the cave was mapped again by Kostas Adamopoulos, Petros Stavropoulos, and Ilias Kazais of the Speleological Hellenic Explorers’ Association (S.EL.A.S.), with the results of the measurements recording a new depth of – 110m.

From August to October 2014, the THISEAS Exploratory Association carried out a series of expeditions to the cave in question, discovering new sections parallel to the main direction of the cave, reaching -130m, but without mapping them.

In September and October 2023, a multidisciplinary mapping effort of the cave brings to the surface its exact dimensions, its true maximum depth, and its parallel routes, thus shedding light on years of effort. The expedition which took place on 23-24/09 – 30/09-01/10 and 07/10/23 by George Sotiriadis (PROTEAS), Hercules Kopitsas, George Vlachos (E.S.E.), Angel Vlahopoulos (THISEAS), Spyros Maragos and Mpampis Korovesis (SP.EL.E.O.) reached a maximum depth of -113m. for the old branch of the cave and respectively -122m. maximum depth for the new branch.

The Cave

This fault has created a challenging vertical cave with narrow passages in its first few meters.

Its characteristic feature is the gallery created at -70m, which gives access to the opening directly opposite by setting up a large traverse and entering new chambers.

Impressive are the cavernous chambers made of coral, but also the particularly demanding narrow passages that require respect and maximum attention to achieve the least possible stress on the cave by the cavers.

The pit cave Megalos Pyrgos (-122m.) is the deepest cave of Mount Hymettus, among the 70 or so caves that have been recorded in its wider area, to which a series of expeditions have been carried out by all the caving clubs of our country over the years.


On 22/01/2023, we visited and explored this cave and reached the maximum mapped depth of the old branch with members of the Speleological Greek Athletic Association (S.EL.A.S.).

We want to thank Nikos Mitsakis and the senior members of the club, Dimitra Karavanas and Pavlos Graviotis, for the organization and the safe conduct of the expedition.

Finally, we thank George Sotiriadis for permission to republish the cave’s imprint and for the information about the last expedition.

Cavers participated in the project:
Nikos Mitsakis, Dimitra Karavanas, Pavlos Graviotis, Dimitris Synodinos, Evangelos Mitsakis, Konstantinos Pavlakis, Maria Halkiadakis, Odysseas Mitsakis and Andreas Andrikopoulos.
Text editor: Andreas Andrikopoulos
Photos: Konstantinos Pavlakis, Maria Halkiadakis, Andreas Andrikopoulos.




The caves of S.A. Attica – Petrochilou Anna

Yorgos Sotiriadis, PROTEAS

Cave Pit Megalos Pyrgos

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Cave Pit Megalos Pyrgos 37.939575, 23.795879