The city of Budapest is home to the world’s largest known thermal cave system. But there is one undiscovered part of the Hungarian capital’s spa culture that lies beneath the city. Local steaming thermal baths gained a lot of popularity among the visitors, but not everybody knows some of them dated back as far as the Ottoman occupation in the 15th century. However, the source of Budapest’s thermal waters is a curiosity in itself.
One of the major caves uncovered includes the Ferenc-hegy, which showed up during the drainage groundwork, later on Mátyás-hegy cave, which can be visited by amateur spelunkers in the assistance of a guide and finally the József-hegy known for the richest mineral formation in all Buda caves and is open only to researchers. The caves are around 2,200 meters long and the temperature drops to 46 Fahrenheit as you walk down the artificial tunnel leading inside. The cave earned a name of “Underground Flower Garden” thanks to the pinkish mineral formations decorating the walls. Some of them have a shape of small cauliflower heads, the other mineral deposits will remind your flowers.
As you may already know, the famous city’s attractions are located in the Buda part of the city, along with popular thermal baths. But the most exciting part is waiting for you underneath – a complex labyrinth of caves that run underneath the houses and streets of Buda, including the largest underwater water cave -the Molnár János Cave, whose curative water is still pumped into the popular Lukács Baths.
If you walk by the Lukács Baths, stop and take a look across the road, you will see a tiny lake next to the ruined bath. It looks like from Ottoman times, but this forgotten bath dates back to the 19th century, however the biggest mystery lies underneath the lake.
The small pond is known as Malom Lake and has been famous for its thermal and curative properties since Roman times. Back in 1974 the divers have discovered the submerged cave under the lake which measured around 400 meters during the first investigations. But there was much more than met the eye. The water at that time was around 68 Fahrenheit, though divers couldn’t but notice that the walls of the cave somehow were warm as well. Further investigations of the cave continued only in 2000s, this is the time when a totally new cave system was uncovered once divers drilled through the wall and saw the continuation of the cave.
One of the divers- Zsolt Szilágyi dived the cave more than 300 times and worked with exploration teams.
He says: “It was difficult to investigate the cave further since the nearby Lukács Bath gets the water from this cave. There was a pipe that ran into that cave at the time, and we were not allowed to disturb the water too much, because, otherwise the silty water could contaminate the bath. However, in the early 2000s, they moved the pipe to another location, so divers could investigate and found that the cave system continues beyond the first chamber, this marked the start of the new exploration. Until 2011, we found the cave system was around seven kilometers long.”
Nowadays, the Molnár János cave is an active thermal cave and is still being formed. Divers call the water in Molnár János hostile due to the sulphuric acid it contains. There is so much sulfuric acid in the water that it erodes material, especially rubber and metal. The further explorations revealed a complex of network of large caverns, channels and underwater lakes. But unfortunately the further explorations stopped in 2011, after a tragic death of a diver. The caves have been closed for visitors until 2015, and very soon qualified divers will have an opportunity to visit the cave again.
Molnár János would be even more extensive, had the moving earth not cut the tunnels off in many places. The caves almost certainly continue behind places where the fault lines have blocked the way, but they have no entrances.
Today, over five kilometers of the caves have been explored. The biggest charted hall is over 80 meters long and 16-26 meters wide. In this hall alone, there is over 23,000 cubic meters of warm water.
There are several caves in the surroundings of Molnár János, but most of them are not suitable to dive in. They are either too hot or too confined.
featured image: xray-mag