We could smell the subtropical heat and humidity. Everyone who entered the Molnár János noticed that immediately. With every step deeper, the heat intensified, till I felt the sweat running down my back. This was a stark contrast to the cool outdoors of Budapest, thanks to the hot thermal springs that heat up the flooded cave to a warm 28°C. As impressive as the first steps into the cave are, the outside is unspectacular. The entrance to the cave is in the immediate vicinity of the Lukáz thermal bath. No sign, no advertising, just an old sliding gate behind a small car park. Who would guess that one of the most incredible diving sites in Europe were located here?
Stern dark brown eyes inspected every newcomer. These eyes belonged to Attila Hosszú, the only licence holder of the Molnár János in Budapest. He alone sets the rules, and for good reason. Since a diver died in the cave, the government completely prohibited diving, till they approved Hosszú’s licence. Even then, strict measures are in place to prevent further accidents; a diver must be certified with a basic cave diving qualification, have insurance that covers cave diving, and use either open-circuit double tanks or a rebreather. In addition, every dive must be accompanied by a guide.
“It is very important to follow all the rules if you want to return home safely,” Hosszú warns. Inside, the cave system snakes in many directions, up to 100 metres deep. Some corridors converge; others lead to dead ends. Hosszú and his assistants have set up seven kilometres of cave lines, though there is still much undiscovered behind them.“For the moment, we have reached the limit of four to five hours, even with the rebreathers, unfortunately,” Hosszú explains.
We walked through the massive sliding door, which felt like a gateway to another world. Jumping into the warm water, all the warnings were forgotten, and excitement built as we anticipated the impending adventure. A large platform and massive ladder served as an entrance to the large pool. The high rocky walls were suspended with large steel nets to prevent any sudden rockfall from injuring a visitor.
In the light cast by the lamps, the high rocks of the entrance appeared like a synagogue of light and shade, while the pitch-black depth of Molnár János lay beneath us. As we descended into the darkness, our eyes became desperate for a reference, but only the fine sediment that covered the cave walls greeted us even after a few metres into the dark abyss. The high risk involved in this dive became apparent – one buoyancy mistake made too close to the walls would run the risk of zero visibility fast.
I followed closely behind, as after a few minutes, no direct ascent was possible; I sure did not want to get lost in this dark maze. At 10 metres, there was a thermocline layer where the water temperature dropped to 18°C, making a longer penetration without a drysuit impossible. For certain passages, the drysuit is even prescribed, mainly because of the additional buoyancy it provides.
It is a dark world in the cave. As lamps cast their light on the sharp-edged rocks, we realised the unique formations that surrounded us, formed over thousands of years. Tower-high cathedrals of rock were revealed in fractions of a second as camera flashes burst in symphony; and deep columns hinted at the long history of the cave. Who knew such an alien world existed beneath the historical city of Budapest?