The Ravne Tunnel - Part I
The investigation
Article published on 17 May 2013

by Simplicio (EclisseForum)

While we await the publication of Paolo Debertolis’ book about his experiences at the Bosnian pyramids, we shall continue our investigation from the point where we left off, turning our attention now to the Ravne Tunnels, a mysterious system of caves and tunnels dug into a hill near Visoko.

These tunnels are said to have been built using a remarkable artificial material, superior to concrete. Within the tunnel system, apparently, there are strange megaliths, self-propelled ancient tombs, the spirits of ancient beings, weird noises, and mysterious lamps.

The Ravne tunnels consist of a series of passages dug into the rock of a hill near Visoko. The network extends over several kilometres, and contains several branches. According to Osmanagich and other pseudo-scientists involved in working at the site, these tunnels theoretically give access to whole complex of pyramids in the valley of Visoko. They are also a structure in their own right, with particular construction characteristics, and paranormal features.

Carte des tunnels de Ravne - Map of Ravne Tunnels - Source:

One thing found everywhere throughout the complex is water. Some of the tunnels are almost submerged by it, whilst in others it lies just a few inches below the ground – as the Bosnian Pyramid Foundation found during their excavation inside the tunnels. This excavation involved the removal of various underground pipes, probably made of asbestos, put in place in recent times by miners working in the "labyrinth". Their hasty removal made draining water out of the tunnels very difficult, and caused many problems for the excavation work, as we shall see later.

Les tuyaux sortis du tunnel de Ravne - The pipes removed from the Ravne tunnel. - Photos R. Hoyle

One particularly important feature of the affair involves two interlinked aspects: the manner in which the work was carried out, and the safety of the workers.

In reality, excavations were conducted in many of the tunnels, carried out mainly by the Bosnian Pyramid Foundation – but why excavate? Why not simply explore them?

Apparently, they couldn’t just be explored, as some sections have been blocked by sheets of earth or stone, others have been extended, and yet others practically dug from scratch. Browsing the web for news items about these excavations and their modus operandi, we came across a lot of reports about the unscientific and messy nature of the Bosnian Pyramids Foundation excavations, demonstrating yet again a preoccupation with the structure from the point of view of tourism and the media, rather than a concern for serious investigations conducted with scientific rigour.

For a time, the SBRG were allowed to carry out research into the Ravne tunnel with relative freedom of movement, as revealed by some group members’ comments - despite the fact that several of them would not have had the expertise to properly assess this kind of work.

Paolo Debertolis 01/09/2010

In the Ravne tunnel, operations are carried out primarily with a view to facilitating tourist access. However, the way in which the Foundation has chosen to go about this seems crazy.

Paolo Debertolis 03/10/2010

You’re absolutely right about everything, andyvent. But, given that you know the situation, you have to admit that the decision to raise the roof of the tunnel to bypass the lake in order to improve access effectively means altering the dynamics of air circulation in a complex air-conditioned system. Again, not removing that dry stone wall, also for tourism-related reasons, with the possibility of skirting the lake, was another mistake.

Paolo Debertolis 25/02/2011 (re a collapse in the tunnel)

The collapse is due to the fact that they had opened up the regular structure of the tunnel at the beginning of the new section in order, I think, to make it squarer for prop safety reasons (the ogival shape of the tunnel does not allow this) and have more space to move the pump. But they extracted too much conglomerate, and down the whole thing came (a typical example of destructive archaeology). Unfortunately, sometimes the workers do things their way, saying not a word to anyone, leaving you to stumble across a fait accompli, rather like when builders renovate your house and don’t bother telling you what’s going on … and then flood the house next door. Well, it’s no different here.

We’ve come across the same ideas, and similar opinions, from many other sources, including some of the volunteers themselves, and other professionals who have worked on the site.

One of the principal recurring criticisms concerns the fact that many tunnels have been either widened, destroying what could have been the original structure, or altered by excavation activities. It even seems that, in their haste, the excavators are digging channels through solid rock, abandoning any idea of bringing the original structure to light. In partial mitigation, Riccardo Brett, an archaeologist working for the Foundation, told us that, because of a Federation Ministry of Mines decree, they would have been obliged to reshape the tunnel. Very strange, considering that, according to the Foundation, the Ravne tunnels are the remains of an ancient civilization, in which case one might have been expected them to be treated as an archaeological site, rather than as a mine.

Photo de l’intérieur du tunnel de Ravne - A photo of the interior of the Ravne tunnel. - Source:

From the point of view of Health and Safety, it should first of all be pointed out that, while the excavations are being conducted by various workers being paid by the Foundation, there are also many unpaid volunteers working on the project who are not required to have any specific training, and are therefore endangering themselves by working at their own risk.

Riccardo Brett here summarises the instructions given to the volunteers:

First, an exploratory tour, not just the usual tourist thing, but one outlining the general details of the site as regards the work to be carried out, and what we might call a brief "introductory course" that will go on being added to during the working days and meetings about the work.

Evening sessions devoted to collecting data, and organizing teams and tasks for the following day.

Morning briefing with the team leader, and team leader briefing before starting work, with the archaeologist present to check that all details have been covered.

On the first morning, the volunteers are given guidelines to ensure that the work is carried out as safely as possible. Emergency procedures and rules are also explained to them: they are repeated at frequent intervals, in order to ensure that the volunteers will adhere to them. For the duration of the working day, the team leaders supervise the volunteers’ activities ... the archaeologist visits the volunteers in the middle or end of the day, to check that nothing untoward is taking place, to lend a hand, or to see what has been produced at the end of the day.

Here is a video showing the conditions in which the volunteers work, and the excavation techniques practised, in the Ravne tunnels:

Apparently, there have been numerous collapses in the tunnel, sometimes even accompanied by injuries. There have also been several accidents, caused by a combination of untrained personnel, rough-and-ready working conditions, and the use of materials that were either sub-standard, or not adequate to cope with the environmental conditions.

Visitors to the tunnel have told us that beams are rotten, crooked or poorly braced, the roof is unstable, and that the risk of collapse is very high. Despite this, however, the Foundation continues to recruit volunteers who are sent to work in an environment that certainly cannot be described as safe.

By way of confirmation of this point, let us once again quote the words of Riccardo Brett:

In itself, and as a structure, the tunnel is safe. The original structure is solid, and has lasted for years in an area which, as has rightly been pointed out, is prone to earthquakes. The fact is that only two areas, one of them being in the section discovered in June 2012, have experienced slight falls, while all the other areas were clear. What does this tell us? That, if there are collapses, they are the result of the present activity in the tunnel. I’ll try and explain the problem in practical terms. The original form of the tunnel was designed to be self-supporting. When, in compliance with the directives of the Federal Ministry of Mines, and to facilitate the work as well as visits by tourists, the roof was widened, the inevitable happened. It is self-evident that, if the roof is raised above parts where there are layers of sand, and you get back to a layer of conglomerate, the latter does not always reveal whether it is "damp" or solid enough to be stable. As a result, when you proceed to erect the famous wooden scaffolding - which, losing the waterproof covering, etc., applied to it, rots at an even faster rate than two years ago, because of the sections of the tunnel containing water – then the disintegrating material from the roof slowly accumulates on the scaffolding above the wooden beams. Gradually, the weight becomes too much for it, and what happens? You’ll never guess … it collapses.

Finally, we can report that Paolo Debertolis, ever since his expulsion from the Ravne tunnel, has repeatedly, and publicly, sought to distance himself from the Foundation. He now states that the reason why he is distancing himself is that he believes that the Foundation intends to exploit the tunnel intensively, with commercial interests in mind. If readers care to check the dates of some of the quotes cited above, it will become clear to them that Dr. Debertolis suspected as much all along, and took advantage of the mistakes made by the Foundation in order to make himself appear more professional and competent in the eyes of his supporters, attempting to distance himself only after being kicked out by the Foundation.

Concrete and Megaliths

As briefly mentioned above, the Foundation claims that there is a dense network, or maze, of tunnels, built by an ancient civilization in 12,000 BC, inside a hill formed at a date back in 30000 B.C., the tunnels subsequently being closed off about 4600 years ago. Here is a series of statements made on this subject by some of the weird and wondrous characters connected with Visoko.

Paolo Debertolis 04/10/2010

My Croatian colleague has found (the credit is all his!) some very large footprints, perhaps left by people more than two metres tall, wearing some sort of flip-flops.

Moreover, my impression is that the structures are truly ancient, much older than thought, and C14 results giving them a date of 30,000 years are not incorrect. But then I think that, somehow, everything finished up being flooded for a certain period of time. Why, I couldn’t say.

Paolo Debertolis 11/02/2011 (post recently removed)

For now I can give you a heads-up that, following her research (Prof. Krasovec Lucas – Ed.), it seems that the structure of Ravne was built over a small plateau and then covered with earth. [...] therefore, it seems that the Ravne structure consists of ancient concrete formed into a beehive shape, and then placed on the ground.

Nenad Djurdjevic 15/02/2011

"To reveal the chemical composition of the high strength concrete of the Bosnian pyramids would be like revealing the formula for Coca-Cola. I do not think that Osmanagic, who is an excellent businessman, would be so naive and stupid as to do so. Just imagine the value of this formula in construction."

SBRG Article November 2010 (recently amended)

Original text: "The picture that emerges at this point is of a truly awe-inspiring dimension: the builders of the Ravne tunnel did not dig tunnels through the mountain, and then cover their walls with heat-compacted concrete to sustain the earth and rock of the roof; instead, they built the concrete structure from scratch, and then covered it over with earth! "

Changed to:

"The picture that emerges at this point is one of remarkable interest: the builders of the Ravne system dug tunnels through the, following the dictates of a logic that took into account the currents of air circulating inside the tunnels."

(Note the certainty with which everything is claimed, and its diametrical opposite subsequently claimed, despite starting from exactly the same premise. – Ed.)

Paolo Debertolis 21/03/2011

There is a drystone wall on which there is a covering of concrete.

Obviously this wall, of a manufacture and materials similar to those of today, could not have been placed beneath the poured concrete, but dates back to an era before the concrete hardened.

And there are countless other examples of this kind.

In reality, those who have approached the question in a serious and rigorous fashion have concluded that the entire network of tunnels of Ravne consists of nothing more than a series of passages dug through an absolutely natural alluvial deposit. The tunnels seem to have been reused by the civilizations that subsequently inhabited the area, from the Romans to nineteenth-century miners.

On this subject, allow us to refer the reader to a complete and detailed discussion here.

As for the dating, it is enough to mention one single piece of proof: the stalactites and stalagmites found in the tunnel, even in the "ancient" sections, don’t reach a length of between 5-7cm. On average, the rate of growth of these formations is between 0.1 mm and 1 mm per year, which means that, at most, certain sections could be 700 years old, i.e., the Middle Ages.

It even appears that, in a recently opened area of the tunnel, an eighteenth-century miner’s lamp was found, evidence that not only were the tunnels known about very recently, but also that the closure of some sections does not date back to some antediluvian era, but only to a few decades ago. Questioned on the matter, Dottore Brett told us that the lamp could have been brought in to that part of the tunnel by someone using some secondary access, but we didn’t find this explanation too convincing.

Lampe trouvée dans une galerie du tunnel de Ravne - Lamp found in a section of the Ravne tunnel. - Source:

To summarise: no ultra-strong artificial concrete, of which there are no traces and investigations; no structures with cement coverings; no artificial hills; and no ancient civilizations dating back twenty thousand years.

Just a bunch of self-proclaimed experts always sure of their thinking. Even in the face of blatantly contradictory opinions, the self-proclaimed experts take the view that they were right before, and they are equally right now: all of which demonstrates a greater concern for potential book-sales than for solid scientific research.

But also in the tunnel are stones, described by the Foundation as megaliths.

Called K1, K2 and K3, these stones, whose position is shown in the map of the tunnels shown above, have had a curious and troubled history featuring more than one revelation of a scandalous and/or dramatic nature, but they are still one of the tunnels’ main tourist attractions.

Le mégalithe K1 - Megalith K1. - Source:
Le mégalithe K2 à l’intérieur du tunnel de Ravne - Megalith K2 inside the Ravne tunnel. - Source:

Discovered in the early years of the excavations, these megaliths are at the centre of many controversies concerning their nature, their function, the alleged inscriptions and, incredible though it might seem, what they might possibly contain.

According to the Foundation, the material of which they are made is not compatible with the context in which they are found, which would imply either that they were rocks brought there from somewhere else, or that they were "artificial." Sometimes they are described as "ceramic", sometimes as blocks of fine sand or sandstone. Debertolis has made the suggestion that the items were obtained by a process involving the “cooking” of raw material.

In reality, the only reports to which they have succeeded in obtaining access are those commissioned by the SBRG from Dr. Nunzia Croce. These analyses included an examination of three rock samples from the Ravne tunnel, one taken from a megalith, one from a drystone wall, and another classified as a "piece of zoomorphic statue."

The results need no further comment, and are shown below:

From the investigations effected, the following conclusions can be drawn:

• All samples are of natural stone material of sedimentary origin.

• Sample A (Megalith – Ed.) represents a sandstone that can be classified as arkose/lithic arkose – that is to say, a rock containing less than 15% of fine-grained matrix - and that the clasts of which it is composed are represented in various proportions of quartz, feldspar, and fragments from various rocks. The very small matrix component, present mainly along the contours of the clasts and rock fragments, together with the presence of cement consisting of spathic calcite, leads us to rule out the material investigated possessing any artificial nature. Moreover, there is also a "ripple" structure - delineated by alternating laminae of rich dark clay, and light laminae with a lower clay, and higher calcite, content - established by directional water flows operating in non-deposition phase and immediately following deposition.

• Sample B is represented by a fragment of zoomorphic artefact consisting of very fine-grained limestone, composed almost entirely of granules of calcium carbonate of microsparitic size, arising from the deposition of a carbonate mud consisting of fine siltitic particles.

• Sample C (drystone wall) is a fine-grained limestone clast consisting predominantly of calcite clasts (spathic calcite and crystals of metamorphic calcite) composed of fragments of rocks, calcitic in their turn, finer-grained, or from single crystals or small groups of marble crystals (metamorphic calcite). Clastic silicates are represented by small crystals of quartz, and, more frequently, chert, the size comparable to that of the other clastic limestone elements; and fragments of metamorphic silicate rocks. The clay matrix is present at the boundary of the grains, and the cement is carbonate (micritic).

Since this is, in fact, the sole analysis available at the moment (although it has never been published by the SBRG, which prohibits all unpermitted circulation, perhaps because it strips the affair of any aura of mystery), they represent for us the essence of the situation as it stands at the moment, and lead us to conclude that, from the point of view of their constituent elements, the megaliths are purely natural rocks with absolutely nothing artificial about them.

With regard to the function of the megaliths, the Foundation claims that they are covered in symbols, maps, and a form of writing that they maintain is the earliest known. In addition, they state that these markings are evidence proving that the entire complex dates back to an era tens of thousands of years ago, before the great flood beneath which even the entire complex of Visoko would have disappeared.

Reconstitution des inscriptions supposément trouvées sur le mégalithe K1 - Reconstruction of the alleged inscriptions found on megalith K1. - Source:

Some interesting links:


on the T-2 megalith found in the tunnel near Ravne at its significance

Furthermore, it seems that the megaliths serve to indicate locations where underground water channels cross, such that displacing the megaliths causes a protrusion in the groundwater aquifer.

Megalith returned to its original position.

But perhaps the most disturbing thing is the description of some of the megaliths as sarcophagi, sealed containers holding metallic inserts, and actually equipped with their own lids.

In this regard, we turn once again to the words of one of the chief movers and shakers:

Paolo Debertolis 20/02/2011

"Whilst we await the writing up of the preliminary results from the examination of the megaliths, here is a picture of megalith K4 (about 8 tons) [in fact it is K2 - Debertolis often confuses K2 with the elusive K4 – Ed.] which shows perfectly clearly the groove (sealed) separating the two valves of the megalith (which at this point is no longer a monolith). " [see Figure K2 – Ed.]

Paolo Debertolis 25/02/2011

We had to go back to getting an accurate study of the monoliths, never previously effected with the necessary precision. We got some beautiful shots (that we will shortly be posting), and found numerous metal inserts in the lid (yes, the cover itself) that closes the monoliths after the manner of a sarcophagus, remains of the tools that lowered the lid into position from above.

Paolo Debertolis 25/02/2011

Regarding the megaliths, they all have a sort of lid sealing them very tightly. First, the base was constructed in situ, and then the lid was lowered, after which it was sealed with the usual binder. We think that the iron inserts on the surface were part of the tools that were used to move the lid and were then snapped off at the conclusion of the work, the surface being smoothed. But their function is hypothetical. Inside K4 [K2 – Ed.], the ultrasound system has indicated the presence of a metallic body in the shape of an ova, in the area where the head would be. In April, we shall repeat the investigations with metal detectors. But there is no question of opening it at the moment.

Paolo Debertolis 25/02/2011

On the surface of the lid, we found a large number of severed small oval tubes, perhaps used to pour in the liquid substance, which then hardened, creating the lid.

To sum up: at the end of February 2011, the SBRG, through Debertolis, declared themselves convinced that:

 the megaliths were artificial;

 they contained metallic objects;

 they were manufactured on site; and

 they were equipped with lids, and covered in metal tubes.

All delivered with a great deal of pomp and circumstance, absolute certainty, and an air of weighty authority.

The first of these statements, as we have seen, were disproved by none other than the SBRG themselves, via Dr. Nunzia Croce’s report, which was then kept under wraps for years.

But the other points?

After these statements were made, architect Vincenzo Di Gregorio visited the site as part of a collaborative exercise with the SBRG, although unfortunately the collaboration appears to have finished rather badly, in various legal wrangles.

Di Gregorio revealed, both to us privately, and later publicly, that, after a series of surveys using metal detectors and ground penetrating radar, the megaliths were found to contain no metal fragments at all, whether inside or out.

In addition, amongst the links attached to this article, the reader will find an explanation of how the "seam" that was supposed to indicate the point where the lid was joined on, is in fact a simple vein of limestone.

Finally, let us close with the words of an eminent scholar, who investigated the megaliths deploying the utmost scientific rigour:

The K2 megalith was not opened because, with the help of Kingleo’s [Di Gregorio – Ed.] GPR, we realized that there was no cavity and no spherical metallic object inside it, despite the claim made by a Croatian company that had analyzed the megalith the year before. It begins to look as if they cheated Osmanagic and took him for a ride.

The coup de grâce was the petrological analysis carried out by our geologist, who showed that the megalithic was simple sandstone and not ceramic, as claimed by the previous Foundation archaeologist, Mislav Hollos.

So, at least K2, which is the most impressive megalith in the Ravne tunnel, is revealed by our analysis to be simply stone of sedimentary origin. But on this point I think the others are also agreed.

Who is saying this? Why, none other than Paolo Debertolis, using a rare moment of lucidity to confess the unspeakable. The date is 19/03/2012 and the original post can be found here.

At this point, it’s worth noting two things in particular: first, in little over a year, and with all the grace of an experienced belly dancer, Debertolis has passed sinuously from one immutable certainty to another, its exact opposite. More: he has insinuated that Osmanagic was shown up as a fool for having allowed himself to be cheated by the Croatian company. Meanwhile, Debertolis himself, who apparently never gave tuppence for anything that we at Eclisse had to say, in the end found the tables well and truly turned on him. A real turn-up for the book, wouldn’t you say?

So, to conclude: for years now, the Foundation and the SBRG have been producing agenda-based news of a sensationalist nature, usually for no good reason other than that of generating hype. The Foundation, by its very nature, has no interest in revealing the truth of the situation, and continues merrily on its error-ridden way, while, ever since the time of its expulsion from the excavations, the SBRG seems to have undergone drastic changes of opinion on just about any subject you might care to name. Given this situation, the SBRG have lost interest in maintaining a high level of hype on the structures at Ravne, instead refocussing all the attention and sensationalism onto the only aspects still remaining to be "studied" (the subject of our next article). What the megaliths affair has revealed is how, within the space of one year, the SBRG went from one position to its polar opposite. Of all the preliminary hypotheses (or certainties) which formed their starting-points, they confirmed only one, concluding that what appeared to be large stones of sandstone formed in a lacustrine basin in previous eras, were nothing other than ... large blocks of sandstone! Perhaps this is why they have never published their work on this subject in any congress or journal; they would have been forced to admit that they spent months studying stones that eventually proved to be … stones!

We cannot help but wonder, though: if the SBRG had continued to collaborate with the Foundation on the study of the Ravne tunnel system and everything in it, would they have been so ready to admit that it was a natural complex, filled with stones of natural origin?

Controversy with Robert Schoch about supposed signs and maps allegedly covering the megaliths:

Other links of interest:

Tombs, megaliths, and mysterious symbols

The Dentist and the Giant Mussel