There are no craters here spitting fire, no lava, no heat rising off the ground. What you find instead, in the hills above Buzău, is cold gray mud bubbling out of small cones, patiently, the way it has for longer than anyone has been counting. Locals call them volcanoes. They are not volcanoes. Nobody tells you that part.
What’s actually happening under Berca
The real story starts about 3,000 meters down, in a pocket of natural gas trapped in the same layer of rock that once made this area attractive to oil prospectors. As the gas pushes upward looking for an exit, it drags groundwater and clay along with it. By the time that mixture reaches the surface, it has thickened into mud, and the mud piles up into small cones, some barely a few centimeters tall, others reaching 7 or 8 meters. The whole process runs cold, start to finish. What comes out of these cones is cold to the touch, which surprises most people who visit expecting something closer to a real eruption.
Tourism writing about this place likes to compare it to Hawaii, Etna, or Stromboli. It’s an understandable comparison, visually, since both produce cones and both are called volcanic. But those are magmatic volcanoes, driven by molten rock rising from deep in the Earth’s mantle. Berca runs on an entirely different mechanism: gas pressure pushing groundwater and clay up through sedimentary rock, nothing molten involved. The true geological cousins sit near Baku, Azerbaijan, and in Georgia, shaped by that same combination of gas, clay, and pressure.
Found in 1867, protected since 1924
A French engineer named H. Cognand documented the phenomenon in 1867 while prospecting for oil in the area, the same underlying resource that still drives the gas emissions today. The field was declared a protected natural reserve in 1924, one of the earliest such designations in Romania, driven by both its geological rarity and a handful of unusual, hardy plant species that grow nowhere else nearby.
Four fields, two kinds of mud volcano
The Berca-Scorțoasa area holds four distinct groups, split into two categories locals distinguish clearly even if visitors rarely do. Pâclele build cones, small conical hills with a crater at the top where the mud pushes through. Fierbători skip the cone entirely and form flat, bubbling mud lakes instead, a slower, wetter version of the same underlying process. The two named fields open to visitors are Pâclele Mari (the larger cones) and Pâclele Mici (smaller cones, more concentrated), with Fierbătorile de la Beciu and
Fierbătorile de la Berca rounding out the full reserve.
Visiting, in practical terms
A marked hiking trail, part of the UNESCO Buzău Land Geopark network, connects Pâclele Mari and Pâclele Mici directly: 6.2km round trip, about 3 hours, easy difficulty, running through hay meadows and wildflower pastures with a lookout point along the way. Pâclele Mari holds Europe’s tallest mud volcano, a shield-shaped cone with smaller cones growing on its slopes; Pâclele Mici is the continent’s most extensive mud volcano field. One exception to the rain closure: the themed path at Pâclele Mari stays accessible even after rainfall, unlike the rest of the reserve.
Take DN10 toward Brașov to the village of Sătuc, then continue toward Berca, where signs direct you along the remaining stretch toward Pâclele.
It’s open daily, 08:00 to 20:00 in summer and 08:00 to 16:00 in winter, and the entrance fee is small enough to be almost symbolic, a few lei depending on age. The reserve closes on rainy days, which catches most first-time visitors off guard. Wet clay turns the ground genuinely unstable, not just slippery in the ordinary sense, and paths that are normally safe become a real hazard. Check the weather the day before a visit, not just the morning of.
The site has a wheelchair-accessible ramp at the entrance, and pets are not allowed inside. For anything beyond the basics, the reserve’s custodian, Dumitru Roșu, has fielded questions from visitors for years and remains the most direct source of current, on-the-ground information.
Why this still isn’t crowded
Somewhere between 15,000 and 20,000 people visit each year, a number that sounds significant until you compare it to almost any recognizable European natural landmark. This remains, largely, a place Romanians know well and international visitors have barely heard of, mostly because it doesn’t fit the version of Romania most guidebooks sell. Most travelers come here chasing castles and vampire legends. Berca offers something plainer and stranger: cold gray mud, bubbling quietly, doing exactly what it’s done for millennia.
This article is also available in French:
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