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The Journey Inwards: Visiting Molnar Janos Cave

The FlowState team was fortunate enough to enjoy a two-week break to explore the renowned Molnar Janos Cave nestled in the heart of Budapest, Hungary. Here's our adventure.

About The Cave

Budapest is divided by the river Danube. Buda is situated on the west bank while Pest is on the east. The hills of Buda are inhabitated since the Roman times, and it was famous about its thermal water springs. The Lake Malom’s warm water powered mills in the medieval times (Malom means Mill in Hungarian) but they didn’t know where the water comes from.

The spring water discharging from an enlarged fracture of the Buda Marl feeds the artificial Malom Lake, which is drained through a sluice and canal into the Danube beneath the building of the Lukács Bath because of the urbanized environment.

Budapest lies on a geological fault line: the ground cracked along the collision line of the mountains and the plain. The ascending thermal water dissolved many cave passages close to the surface. Because these caves were carved out from the inside from water coming from below, they did not have any natural entrance to the surface. That is the reason why most of the caves laid hidden until the early 20th century, when they were uncovered due to quarrying or drainage groundwork that took place in the area.

One of the caves even more special: the submerged Molnár János cave, which an active thermal water cave located only meters from the Danube river bank. The dry cave of Molnár János begins a few metres above the surface of Lake Malom. In the 19th century János Molnár, a pharmacist, investigated these dry areas and analysed the water of the spring. He believed there must be a water filled cave system somewhere under the hill.

The first underwater explorations started in 1950’s. In the 70’s and 80’s the divers of the FTSK Delfin dive club successfully explored and charted more than 400 meters of the cave system. They dived regularly this “old part” but in 2002 they found a new passage. The new part was huge, for example they charted a 86 meters long, 15 meters high and 27 meters wide hall. The cave system stretches out to more than 6 kilometres, but there are still plenty to discover in the depth.

The cave is a good example of modern phreatic hypogenic caves, since it has been formed by mixing corrosion below the water table. Mixing corrosion occurs where flow systems of different orders (with different chemistry and temperature) meet via tectonic lines or through diffusion. Besides the tectonic control, the network maze of cave passages follows the south-southwestward dip of the Upper Eocene limestone and marl.

Our Impressions

We personally have mixed feelings about this experience, and here's why. Budapest, located in the heart of Europe, made it incredibly easy to reach. Hopping on a direct flight from Tenerife was the most convenient option. The cave is situated right in the middle of the capital, so upon arrival, you can check into your hotel, gear up, and be diving in just 20 minutes.

However, what we found difficult to accept is the commercialization of this cave. The operator purchased property and drilled a hole to create an entrance. This means you can't freely explore the cave; instead, you have to pay a rather hefty fee for each dive. While this shouldn't be a problem, they typically organize groups with local guides, which goes against one of the golden rules of cave diving. These groups can consist of up to 7 divers at times. Experienced cave divers may not be comfortable with this, so the option of a private guide is available for almost twice the original price.

Another concern is the depth of the cave, reaching over 80 meters in some areas, with most routes starting below 30 meters. This immediately leads to decompression dives. However, it seemed that the planning for these more serious dives was somewhat overlooked by the operator. Without proper planning, divers could find themselves in serious trouble quickly.

Furthermore, it's disappointing that you're unable to use your markers due to the main line being an extremely thick rock climbing rope. Instead, you must rely on preinstalled markers, which can make experienced divers anxious.

The dive center is very busy, with about 100 divers rotating through each day (in winter months). This creates a bit of chaos, especially since the center is located in a basement with limited space. However, despite these challenges, the cave itself is truly amazing and definitely worth a visit. Just be aware of these intricacies before diving in.

In summary, if you're a beginner cave diver looking for a straightforward experience and can trust your assigned guide, this could be a good option. However, for experienced divers, we would not recommend diving here in its current form.



I was really curious about this cave, it seemed quite the unusual spot for a dive site (right in the middle of a hugely populated city). However I guess Earth and its tectonic plates movements could not care less of where humans would settle :)

Hopefully it did not stress you guys out too much. Shame that it has been commercialised in such a way that you must pay for entrance. I guess though at least there will be some sort of control over the divers getting in there, since they must show they have the right skillset to part take in the tours?

Peter G
Peter G
Apr 12
Replying to

Sure, while it's commendable that they demand certifications and insurance, it seems like they're neglecting other crucial practices, like ensuring proper team size and utilizing line markers. Prioritising these aspects would be more essential, as simply checking certifications primarily serves to protect them from legal action.

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