Velebita - world deepest underground pit

Rožanski kukovi, National park North Velebit, Croatia





Cave explorers from Speleological section Velebit with  a few other Croatian clubs  discovered in 2004. a pit inside a mountain Velebit in central Croatia believed to have the world's deepest subterranean free-fall vertical drop, at nearly 513 m. At the foot of the Velebita cave are small ponds and streams, including one of the largest known colonies of subterranean leeches. It is located in the Rozanski kukovi area of the National park North Velebit  in the rocky Velebit mountain range in central Croatia.

Results of expedition Velebita 2004.

Climate: During the expedition in 2004. the cave microclimatic parameters were monitored and some additional physical measurements were performed in the cave.
The temperature and relative humidity of the cave atmosphere were measured on 14 locations throughout the cave. Cave air temperatures ranged from 5.8 oC to 3.2 oC, while RH values ranged between 70% and 96%. The driest conditions were encountered close to the entrance, where the air circulation dries the cave passages below. The maximum wind speed at the entrance was 2.5 m/s. The highest air temperature was in the entrance chamber. At the entrance of the big shaft at -100 m, the temperature lowered to 4oC. In the shaft it was continuously lowered to 3.2 oC at -200 m, and then raised to 4.7 oC at the bottom of the shaft at -580 m. The water temperature at the bottom was 3.6 oC.

Croatobranchus mestrovi - endemic stygobiontic leach found in the Velebita pit at -580 m. Photo: D. Paar

The most important biospeleological find: Numerous troglobitic species were identified in collected material. Among them the most important are small snails from the genus Zospeum, terrestrial isopods from the genera Titanethes, Alpioniscus and Androniscus, millipedes from the genus Haasia, pseudoscorpiones from the genus Neobisium and numerous springtails and beetles from the genera Astagobius and Spelaeodromus. The largest colony of endemic troglobitic leech Croatobranchus mestrovi so far was found in the Velebita Pit, and one and only specimen of the troglobitic harvestman, probably from the genus Hadzinia (Bedek & Ozimec, 2004).

Vertical pit named Divka Gromovnica (513 m),  photo: D. Bakšić

Specific features: Velebita pit had the largest subterranean shaft in the world (P 513)

Cave exploration continued in 2005. and 2007. The result of the exploration is a new cave depth -1026 m. The second entrance was found. The Velebita cave system is the third pit deeper than 1000 m in the National park North Velebit (Croatia).

During the expeditions, physical and chemical measurements were performed in the pit (water analysis, measurement of microclimate parameters, natural radioactivity measurements).

The cave exploration and scientific research is supported by National park North Velebit - project of speleological and biospeleological explorations of the park, The Speleological Committee of the Croatian Mountaineering Association, Croatian waters, and private donators.

Expedition Velebita 2007. New cave depth is -1026 m.
oto: D.Paar


PDF Physical and Chemical Research in Velebita pit (Croatia)
Dalibor Paar, Magdalena Ujević, Darko Bakšić, Damir Lacković, Ana Čop, Vanja Radolić

Bakšić, D., Paar, D., 2006: Croatia and the Deep Caves of Northern Velebit. Alpine Karst, vol 2., ed. J. & T. Oliphant, 105-124, Cave books, Dayton, USA.

Kuhta, M., Bakšić, D., 2001: Karstification Dynamics and Development of the Deep Caves on the North Velebit Mt. – Croatia. 13th Internatinal Congress of Speleology, 1-4, Brazil.

Lacković, D., Šmida, B., Horvatinčić, N., Tibljaš, D., 1999: Some geological observations in Slovačka jama cave (-1268 m) in Velebit mountain, Croatia. Acta carsologica 28/2, 113-120, Ljubljana.


In the cave. Photo: D. Bakšić

In the 513 m long subterranean shaft.
Photo: D. Bakšić

More about the exploration of deep caves in Croatia and contact info

Text: Darko Bakšić, Ana Bakšić and Dalibor Paar



Name: Cave system Velebita

Location: Rožanski Kukovi – Crikvena, National park North Velebit, Croatia

Entrance at altitude: 1,557 m

Depth: -1026 m

Horizontal length: 1206 m
Length: 3176 m

The largest shaft: 513 m

Cave discovered by: Speleologists from the Speleological section of the University Mountaineering Association "Velebit" (SOV) on 31 July 2003.

Period of exploration: 2003, 2004, 2005, 2007., 2008.
Explorers: SO Velebit, SO Dubovac, SO Mosor, HBSD, SO Željezničar, SK Samobor , PK Split, KS HPS


Cave system Velebita (2008.)


Morphology: The entrance to Velebita Cave descends freely between lodged boulders to the entrance chamber, which is well lit by daylight. Between the boulders and the compact rock on the floor there is the Svarog Passage, which leads to an over-hanging shaft of 28 m. The bottom of the shaft is 8 x 4 m in size. It is situated at a depth of –40.6 m and is covered with chock.

Velebita entrance is not too big. Photo: D. Paar

In the north-west of the chamber there is a fissure – a half-metre-wide Stribor's Passage with an occasional air flow.
The channel slopes down over the clay-covered lodged boulders to a depth of –50 m. At this point there is a passage to the west that ends with a chimney. A shaft of 25 m continues downwards from a double belay in the ceiling. The rope in the shaft is slightly away from the ledge in order to reduce the danger of stones and rubble being pulled down.
From there, the traverse leading to the safest entry point to the next shaft is placed at a depth of –74.6 m. The reason is an opening in the floor and the unstable stone blocks. At the end of the traverse, in the southern part of the main passage there is a large passage to a parallel meander – Palčić meander, which goes back southwards to the neighbouring pit of Breskva. The northern branch of the meander, called Malik's Game, is wider and more indented than Palčić meander. In its northern part it diverges in two branches, both ending with shafts. One of them descends to a depth of –110 m and the other to –114 m.
In the main passage, behind the traverse, there is a shaft of 23 m leading to Perun's meander. From the point at which the boulders are reached with a rope, a slope leads southwards to the Perun shaft branch. The shaft measures 38 m. It continues northwards as a tight meander till it reaches another shaft of 16 m. There is a small chamber at a depth of –161 m, from which a narrow meander leads up to a point where no further advance is possible unless the passage is widened.
The meander of Perun is a high and wide crack – a high meander whose ceiling is out of sight. A narrow meandering fissure is cut in the floor. After about 10 m of horizontal passage and a 5 m drop, a chamber with drip-water is reached. From there, a sharp bend turns west and after another drop of 5 m there is a shaft at a depth of –105 m connected to the shaft of Divka Gromovnica. This is the lower entrance to the shaft, 469 m above its bottom. From –105 m to –210 m the Divka Gromovnica shaft has an elliptic shape, with an average size of 8 x 3 m. At a depth of –210 m the shaft widens (joins a wider shaft) to a size of 40 x 15 m and continues as such to the bottom.

Bivouac I at -580 m. Photo: D.Bakšić

The bottom part of the Divka Gromovnica shaft ends with a sloped chamber covered with big boulders. The rope reaches a point at –574 m and afterwards the floor slopes down westward to the lowest point at –580 m. In the southern part of the chamber there is a 10 m wide, shallow drip-water pool, and in the south-eastern part there is a small shallow drip-water pool with a diameter of 40 m, where about 10 leeches were found. A few meters from the bottom, on the west wall the air comes out through a narrow fissure.

In 2005. we placed the ropes in a different way and managed to enter to the meander 40 m above the old bottom, thus avoiding 150 overhanging wall at the bottom of Divka Gromovnica shaft. We entered to the meander by traversing the sloping ledge followed by 13 m drop. Through meander with clay covered bottom one walks in direction south for 15 meters passing another smaller drop of 5 m. Meander leads to the entrance to the shaft stretching in direction NE-SW, and the shaft ends after 93 meters on the ledge covered with stone blocks (Bjesomar’s ledge). Bjesomar’s ledge closes In NE direction, but it continues in SW-W direction. One descends for 138 m, passing 4 smaller ledges created by lodging of stone boulders in vertical meander, to the next larger ledge (on the depth of -785 m) where it is possible to walk freely. In the center of pebble covered ledge is a huge stone block. Below it is a passage where one walks near 10 m high drop. This 10 m high drop is actually shaft connecting to the main channel from the north side. After 30 m of length the ledge has a knee shape turning first in direction NW, and then sharply in SW direction. This ledge could be used as a place for bivouac for next expeditions. The pit narrows from this point on, and through vertical drops continues through the meander in SW direction. Here also starts the permanent water flow continuing till the present bottom of the pit. The first drop is 65 m high and ends at the ledge with drip-water. On this ledge we widened, by moving the stone blocks, the passage through the meander leading further in deepness (precaution should be taken due to the possibility of collapsing stones). One reaches the bottom on the depth of -941 m (in 2005.) by passing shafts of 19, 25, 18 i 27 m. The rope is placed to maximally avoid the water, but in two last shafts one descends through strong drip-water. It should be mentioned that the weather condition in august 2005 caused higher water level in the pit. The present bottom of the pit is a chamber named The quest of Potjeh. In the north part of the chamber there is a narrow meander with new water flow joining the existing flow that lessens in narrow meander in south part of the chamber. Both meanders are narrow and should be enlarged in order to pass further.

The passage at -785 m. Photo: D. Paar

The entrance to Dva Javora (Two Maples) Cave is 66 m northwest from the entrance to Velebita Cave. The Cave of Dva Javora also has a cave entrance 7.3 m below the entrance of Velebita Cave. The entrance is a vertical crack of 5 x 0.5 m. The cave has a cascading shape and descends to a depth of –12 m in three short pitches of 2 m, 3 m and 3.5 m. The entry part is the narrowest point between 0.3 and 0.5 m wide and between 5 and 3 m high. At a depth of 12 m there is a tight passage to a vertical meander, followed by a shaft of 70 m to Bear Chamber. At a depth of – 62 m (at – 55 m from the entrance to Dva Javora Cave), to the west, there is a traverse through the meander (named Žrek's traverse) to the highest point of Divka Gromovnica shaft (the total shaft length is 513 m).