90 years of organized speleology in Bulgaria

A brief history and main achievements of Bulgarian cavers and speleology

The year 1929 is considered as the birthday of the organized caving and speleology in the country, when the First Bulgarian Caving Societywas found.The idea behind this society appeared about 50 years earlier, right after the Liberation of Bulgaria from the Ottoman empire.

Earlier information about Bulgarian caves had been reported mainly by travelers, clerics and merchants. The first known written description of a Bulgarian cave is from 1640 in a manuscript kept in the Vatican library. It is written by Petar Bogdan (1601–1674), a patriotic Bulgarian, historiographer and a diplomat, a Catholic bishop and the first archbishop in Bulgaria, the author of the first Bulgarian history (from 1667, a century before those of Paisij Hilendarski).

Soon after the Liberation of Bulgaria in 1878 several the scientists pointed their attention towards the caves already known by locals and easy to access, and began their exploration. The first troglobites were described by Hungarian biologist Edward Merkel in the Central Balkan mountain. The works of the archeologists brothers Karel and Herman Skorpil are rich of information about various Bulgarian caves (“Underground resources, found in whole Bulgaria” – 1882, “Natural resources of whole Bulgaria” – 1884, and esp. “Krazh features in Bulgaria”, 1900). In 1891 the first archeological excavations in caves began around Dryanovo.

From the beginning of XX century are the first geological, hydrogeological and geomorphological studies of the Bulgarian karst (made by Georgi Bonchev, Petar Petrov, Zheko Radev). The systematic biospeleological studies in Bulgaria were founded by acad. Ivan Buresh in 1922.

The First Bulgarian Caving Society (1929 – 1949)

The First Bulgarian Caving Society was foundеd on 18 March 1929 in the Museum of Natural History in Sofia. The act gathered specialists in different branches of speleology and cave enthusiasts and was initiated by the hydrogeologist eng. Petar Petrov. Botanist Prof. St. Petkov was elected as the first chairman of the Society. The society had regional branches in Rakitovo and Dryanovo (and some others for a short time). The society had a lot of activities in the years before WW2.

Rafail Popov

One of its most active members was the prominent archeologist Rafail Popov (1876 – 1940), director of the National archeological museum in Sofia.

Мid and Late Paleolithic remains, as well as a full skeleton of a cave bear had been found in “Bacho Kiro” cave by a large Bulgarian-British expedition in 1936. In 1937 “Bacho Kiro” was opened for tourists, becoming the first show cave in Bulgaria.

In 1949 the society was terminated by the communist party due to the change of the political system in Bulgaria.

In 1958 the Committee for Cave Tourism was founded as a branch of the Bulgarian Tourists Union. Later on, it became National Committee of Caving and Cave Tourism (1963), Bulgarian Federation of Caving (1972), Bulgarian Federation of Speleology (1991). Three main periods can be marked within the last 60 years.

Rebuilding of the organization, founding of the register and the rescue team (1959 – 1979)

The 20 years (from 1959 to 1979) were a period of rapid development of the organization. The popularity of caving grew fast and, respectively grew, the number of cavers. The number of caving clubs/sections exceeded 50 in the whole country. A lot of large caves were waiting for their explorers at that time, it was necessary just to ask locals to show them. Acknowledged leader of the caving society in this period was Petar Tranteev, “The Herr” (1924-1979).

In 1972 the Main Register of Bulgarian Caves was created, administrated by eng. Radush Radushev – “Uncle Radush” (1911–1991). The register set some standards on the quality of survey and documentation of new caves. For the purpose of the register Vladimir Popov proposed in 1976 zoning of the karst in Bulgaria, based on geological and geographical continuous structures and features. Bulgaria was partitioned into 50 karst regions within the 4 physico-geographical areas. By the end of 1979 more than 2800 caves were put in the register.  

Bulgarian cavers participated in many international expeditions and events. They became well known with their research and sport achievements in the largest caves in the world. Since 1967 Bulgarians have participated regularly in explorations of the longest gypsum caves in Ukraine.

In 1969 a Bulgarian expedition to the deepest cave in the world at that time – Gouffre Berger was organized. Two participants succeed to reach the bottom of the cave at -1122 m – Annа Taparkova and Petar Beron. With this decent Annа Taparkova became the first woman in the world to reach such a depth underground.

In 1973 a Bulgarian expedition to the new deepest cave in the world Pierre Saint-Martin (-1171 m), was organized. Three persons (Anna Taparkova-Pencheva, Vasil Nedkov and K. Yonchev) from the team succeed in reaching the bottom of the cave doing the travers through Tête Sauvage. Anna became the first woman to reach the bottom of Pierre Saint-Martin.

The first scientific experiments by Bulgarian cavers, staying in a cave for a long time in isolated constant environment and collecting medico-physiological data for their adaptation, were done in 1971 and in 1977 respectively. Four men (Ivan Petrov, Georgi Yolov, Georgi Trichkov and Dimitar Zhishev) took part in the first 30-day experiment, which took place in Topchika cave near Dobrostan in 1971. The second such experiment took place in the cave Desni Suhi Pech near Dolni Lom in 1977. Two cavers, Alexey Jalov and Stefan Tsonev, spent 62 days underground, the longest such experiment in Bulgaria up to now.

The beginning of the organized cave rescue in Bulgaria was set on 31st October 1974 at the constituent assembly in Sofia. Petko Nedkov was the first chairman of the Emergency Rescue Squad having Trifon Daaliev and Vasil Stoitzev as deputies.

The biospeleologist Petar Beron was а part of the team in a 5-month British speleo-expedition in Papua New Guinea, 1975.

Towards new deeper underground horizons with the SRT

This period (1980-1993) began with the adaptation of the Single Rope Technique on national level and the unification of the rigging standards. Two manuals on this technique were published and helped a lot in that direction: “Vertical Speleology” by Mike Meredith (translated in Bulgarian) and “ABC of the Single rope technique” by Petko Nedkov. Thanks to the new technique and the better training of the cavers, some of the most difficult caves were extended and new passages were found. There were not so many unexplored open entrances anymore, but many new were revealed by digging.

This period is marked also by the first steps and successes of the cave diving in Bulgaria, where leading role had Studenets caving club in Pleven. Unfortunately, some terrible diving accidents occurred as well (Popov Izvor – 1981, Urushka Maara – 1989).

In 1980 Bulgarian Federation of Speleology organized the European Regional Conference of Speleology of UIS, with 250 participants from 17 countries. It created a bridge between cavers from both sides of the iron curtain, which was an important step for consolidation of the European speleology.

Dimitar Raychev

In 1980 the Museum of Speleology and Bulgarian Karst was built in Chepelare, which is the only cave museum in Southeastern Europe. Great merit for this act had Dimitar Raychev – “The Sir” (1922-2002), a teacher from Chepelare and a person, devoted all his life to the speleology and the caves in the Rhodopes.

In 1981 the National Caving House “Petar Tranteev” was built in a reach of the karst phenomena area near Karlukovo. Its purpose was to serve as a training and assembly base for all cavers in Bulgaria.

The international recognition of the Bulgarian speleology was growing. Up to 1989 the biggest national and international expeditions were supported financially by the state, many ambitious expeditions were conducted in Austria, Cuba, Greece, Vietnam, India, USSR, France, Spain, etc.

In December 84, during a Bulgarian expedition to Jean Bernard (the deepest cave in the world at that time with -1358 m) four people succeed to reach the bottom of the cave – Senko Gazdov, Krasimir Petkov, Valeri Mirchev and Tsvetelin Mirchev.

Two expeditions were organized in 1986 to Snezhnaya cave -1370 m (the second deepest cave in the world at that time). The first expedition included only 5 cavers from Bulgaria and all of them (Orlin Atanasov, Kamen Bonev, Yuli Yuliev, Rozalin Stanchev and Filip Filipov) succeed to reach the Hall X at the bottom parts of the cave.

The main goal of the second expedition was to pass the traverse Mezhonnogo-Snezhnaya. Mezhonny is the upper level of the system and the denivelation of 1370 m is measured from that entrance. Two women – Anna Pencheva and Diana Pencheva reached the depth of 1355 m (Hall X at the bottom parts of the cave), where the collapse stopped them to reach -1370 m. They entered through the Mezhonny entrance to the bottom of Snezhnaya together with Kiril Ivanov and exited through Mezhonny. This was enough for a new woman deep descend world record. Vladimir Grancharov and Ivan Angelov traversed through the entrance of Snezhnaya to the Hall X and exited through Mezhonny. Nasko Lambov accomplished a descent to the Hall X from the entrance of Snezhnaya and returned back.

22 years later (December 2008 – January 2009) Teodor Kisimov participated in an expedition to Illyuzia-Mezhonnogo-Snezhnaya (second deepest cave in that time) and reached the bottom -1753 m from Illyuzia entrance. After more than 20 years this expedition made new discoveries at the bottom: The Throne Hall and The lake of Al. Morozov.

It is fair to give a due tribute to the considerable success of the Bulgarian cave divers abroad, crowned by the penetration of the siphons in the giant Spanish pothole BU-56 (Sima de las Puertas de Illaminako Ateeneko Leizea). Three Bulgarian expeditions were held in 1986, 87 and 88. As a result on September 11, 1987 the depth of the pothole Bu-65 reached 1408 m after successful dive of Ilko Gunov, Milen Dimitrov and Valentin Chapanov and for some time the system was the second deepest in the world.

In 1989 the expedition in Algeria was conducted and three people – Orlin Atanasov, Martin Tranteev and Rosen Piskov reached the bottom of Anou Boussouil Cave -805 m. This is the onlyBulgarian expedition in such a deep African pothole.

Contemporary period

The period after 1993 began with a deep economic crisis in Bulgaria with an impact to the whole society and its activities. Many clubs terminated or strongly decreased their activities. In the new century some of them were restored and some new were founded. The Bulgarian Federation of Speleology became an independent, nonprofit organization, not as previously a part of the Bulgarian Tourists Union. Difficulties to find funding changed the style of our expeditions, they became shorter but more intensive, with less but capable and strongly motivated people.

Priority in the international calendar was given to closer and perspective destinations, mainly on the Balkans.

Since 1991 systematic cave exploration expeditions have been organized in Albania, including systematic studies of karst and ethnology in the mountainous area of Golo Brdo, area inhabited by ethnic Bulgarians. Great support to the Bulgarian cavers, esp. in organization and logistics of these expeditions from Albanian side was given by Prof. Gezim Uruci (1949-2012) from the University of Skoder “Luigj Gurakuqi”. As a result of explorations 1991-2019 more than 100 caves were found. The deepest one is BB3-30 with -610 m, Cave Ru (-574 m) is with the biggest vertical pit in Albania -360 m and 21st in the World; Cave Maya Arapit, which entrance is on the foot of Maya Arapit peak (2217 m), so called Albanian “Matterhorn” is with +387 m and -26 m and is still object of explorations. Shegan spring was explored to a length of 86 m and up to the depth of 64 m by Orlin Kolov and Alex Kirov.  

In 1997-1998 Tsvetan Ostromsky (during his post-doctoral research in Purdue University, Indiana, USA) participated in the exploration and surveying of new parts in the longest cave in the world – Mammoth Cave System (by now 640 km. long), in Kentucky, USA and other caves in MCNP, joining several expeditions of the Cave Research Foundation (CRF).

Emiliya Gateva

In 1997 Emiliya Gateva spent alone 52 days in compete isolation in the 100-meter deep cave Pticha dupka in Troyan Balkan. This was the third experiment of this kind in Bulgaria, following the experiments in Topchika (1971) and in Desni Suhi Pech (1977), but the first with just one person and the first accomplished by a woman.

Bulgarians took part in the exploration of the deepest cave in Turkey, EGMA (-1429 m) in 2004 and 3 people reached the bottom – Teodor Kisimov, Konstantin Stoilov, Svetlomir Stanchev. Other three participants reached about -1300 m: Tsvetan Ostromski, Nikolay Tomov and Nikolay Kamenov. In the following years several Bulgarian cavers participated in expeditions in Turkey together with Turkish and Ukrainian cavers (at most, 5 – in Aladaglar 2008).  Teodor Kisimov reached the bottom of the caves: Kuyu Kule -832 m in 2006 and Kuzgun -1400 m in 2013. In the beginning of September 2019, three cavers from Bulgaria: Teodor Kisimov, Dilyana Hristova and Georgi Berov participated in the Morca expedition in Turkey, where the depth of 1240 m has been reached (just preliminary calculated number, the exact depth is subject to official confirmation). With this Georgi Berov became the youngest Bulgarian caver to descent below 1000 m underground.

In 2004 four Bulgarians participated in an international expedition to Jama na Vjetrenom Brdima Montenegro. Encho Enchev and Zhelyazko Mechkov rigged the way to the bottom (it was the first descend after 1986 to the bottom of the cave). During this expedition and previous in 2002 (led by ASAK- Beograd caving club), the cave was re-surveyed, (using more precise instruments), which showed that the previous mappings had a considerable mistake, about 120 m. The correct depth of the cave is -775 m.

Bulgarian cavers participated in the exploration of the deepest cave in the world at that time Krubera-Voronya in 2005 and 2013. Two cavers reached the bottom at -2080 m in 2005 Teodor Kisimov and Konstantin Stoilov. Later on, in 2013 Teodor Kisimov reached -2145 m, this is the maximum depth reached by a Bulgarian caver, and Konstantin Stoilov descended to -2080 m.

Bulgarian-Russian expedition to Sarma Cave (-1549 m at that time) was organized in December 2007 – January 2008 with the purpose of continuation of explorations at the bottom and in the unexplored sections of the cave in order to increase its depth and bring it to the forefront among the deepest caves in the world. Five people reached the bottom: Zhelyazko Mechkov, Pavlin Dimitrov, Aleksander Kolev, Igor Runyashki and Svetlomir Stanchev.

Bulgarians participated in the explorations of the Deepest pits of Dinaric karst: expedition in Lukina jama -1421 m in 2010 (all 4 participants reached the dry bottom at -1368 m), Velebita -1026 m (the cave with the greatest free fall vertical pit in the world -513 m) in 2012 (again all 9 participants reached the bottom) and Slovachka jama -1324 m in 2017. Four Bulgarian cavers succeed to reach the bottoms of all of these caves: Antoniya Vlaykova, Encho Enchev, Vladimir Georgiev and Yavor Tzvetanov.

Since 2015 the Bulgarian speleologists Stanimira Deleva and Angel Ivanov are actively involved in the development of the cave exploration and biospeleology in Costa Rica with a long-term research and conservation project, focused on bats and cave fauna.

Successful end of the expedition 2019 “Malham Cave Project – The Longest Salt Cave in The World”, Israel

Bulgarian cavers, together with Israeli researchers and an international team surveyed the longest salt cave in the world – Malham in Israel (about 10 km), as a result of two expeditions in 2018 and 2019.

Systematic research in a series of expeditions is still going on in Austria. The history of the Bulgarian explorations in the Tennengebirge massive in Austria started in 1980. In the years between 1980 and 1983 our teams explored more than forty vertical caves ranging from small ones to maze ones with a depth close to -600 m. All of these were wet and cold alpine caves, with entrance shafts often filled by snow and ice. A total of 3252 m depth of caves was discovered and surveyed. The deepest caves were: S1 (-584 m), S2 (-460 m), S20 (-374 m). The explorations stopped in 1983, but later continued at the 30th anniversary, in 2013 with a small reconnaissance trip to get to know the area. For the past six years (2014-2019), there have been new discoveries – about 2000 m in total of depth was surveyed. Cave S20, discovered in 1983, is now -570 m with still unreached bottom.

Bulgaria in the international caving organizations

In 1965 Bulgaria became one of the founding countries of the International Union of Speleology (UIS). Throughout the years Bulgarians have significant contribution to the work and representatives in the governing bodies of some of its commissions. From 1993 up to now Yavor Shopov is a president of Physical Chemistry and Hydrogeology of Karst Commission of UIS.

In 1980 Bulgarian Federation of Speleology organized the European Regional Conference of Speleology of UIS, with 250 participants from 17 countries. It created a bridge between cavers from both sides of the Iron curtain, which was an important step for consolidation of the European speleology.

The International Cave Rescue School in Vratsa was organized in 1988 by the Bulgarian Federation of Speleology in Vratsa. In 1989, Trifon Daaliev was elected as a secretary and in 1997 he was elected as a First Vice President of the UIS Cave Rescue Commission and he is still at the same post. In 1991, Bulgarian federation of Speleology hosted the International Cave Rescue Conference.

In 2009 UIS granted the book “Caves and Speleology in Bulgaria” by P. Beron, Tr. Daaliev, A. Zhalov the UIS Award for “Most Significant Speleological Publication”.

In 2011 the 12th International Cave Rescue Conference was hosted in Bulgaria, Dryanovo with more than 100 participants from 15 different countries.

In 2016 Antonia Vlaykova became President of the European Cave Rescue Commission (ECRC) of the ESF.

The 11th European Cave Rescue Meeting took place in Sofia, Bulgaria in 2017, organized by Cave Rescue – Bulgaria on behalf of the European Cave Rescue Association (ECRA).

Bulgarian Federation of Speleology is a member of the European Speleological Federation (ESF). Bulgarians are involved in a number of Euro Speleo Projects.

Bulgaria was an initiator and founder of the Balkan Speleological Union and hosted two of the Balkan Cavers camps (the 1st in Teshel – 2007 and the 10th in Vraca – 2016).

Some significant scientific and applied achievement of the Bulgarian speleology

Bulgarian biospeleologists have conducted researches in many countries, mainly in the Balkan Peninsula, but also in Cuba, Turkey, Tunisia, Vietnam, China, Mexico, Laos, Slovakia, Kenya, Tanzania and many others. They studied in more detail Corsica, Greece, Albania, and China in several expeditions with the participation of Petar Beron and Boyan Petrov.

Peter Beron – biospeleologist, world-recognized scientist and long-time chairman of the Bulgarian Federation of Speleology. Thanks to his high spirit, he continues to be an active caver for over 50 years

After a series of catalogs by V. Georgiev and Petar Beron and two reviews in 1962 and 1994, in 2015, a monograph on the entire cave fauna of Bulgaria was published by Peter Beron. The book contains information about 866 species of animals from 813 caves. Many new species and families of animals have been found for the first time by Bulgarian biospeleologists. There are 90 new species and 7 families of animals, named after Peter Beron. In New Guinea, fundamentally new things have been identified – sea relicts on the mountain peaks, troglobions in cool caves around the equator.

During later archaeological excavations in Kozarnika cave near Gara Oreshets, some of the earliest evidences of human habitation in Europe were found, dated 1 400 000 – 1 600 000 BP.

Series of valuable international events in the field of karst sciences were organized by teams of Bulgarian speleologists. Among them were the symposia on “Cave Climate and Paleoclimate – Best Record of the Global Change”, the schools on “Karst and Current Problems in Speleology”, a series of forums on “Protected Karst Territories” and many others.

The only lava tubes in Central and Eastern Europe have been proven thanks to prolonged research of Boris Kolev on over 80 lava caves in the Rhodopes. Bulgarian speleologists discovered a cave of a new type of formation: corrosion-erosion cave in gneisses.

Yavor Shopov discovered that luminescence has bands as thick as microns and that these individual bands represent an annual cycle – a phenomenon, named by Prof. S.E. Lauridzen “Shopov-bands”. Based on these observations several new methods were developed for study of cave processes in the past and a new scientific field was defined – Paleoluminescence. These studies have attracted great interest of scientists from other areas to the study of processes in caves. Commission of Physical Chemistry and Hydrogeology of Karst of the International Union of Speleology (UIS) has implemented the international program on “Luminescence of Cave Minerals”, led by Yavor Shopov.

In 2013 the Physical Chemistry and Hydrogeology of Karst Commission of UIS started International Programs on Remote Location of Caves (RCL) headed by Prof. Yavor Shopov (Bulgaria) and Dr. Ivo Baron (Austria) and International Program on Cave Research (IPCR) headed by Prof. Yavor Shopov (Bulgaria) and Dr. Giovanni Badino (Italy).

In 2015 Bulgarian speleologists Stefan Shanov and Konstantin Kostov published the monograph Dynamic Tectonics and Karst (in the series Cave and Karst Systems of the World by Springer).

In 2011 National Geographic Channel made a film based on research in Duhlata Cave, Bulgaria.

Bulgarian cavers developed some instruments and gadgets for cave exploration and cave rescue (V. Markov, V. Gyaurov, N. Landjev, and others). Nikola Landjev developed and manufactured world class cave equipment known under his trademark “Landjoff”.


Kolkina dupka Cave (-542 m), the deepest one in Bulgaria

Currently there are more than 6000 documented caves in Bulgaria. There is still a lot to discover in many Bulgarian karst regions.

The longest cave – Duhlata (18600 m) and the two deepest – Kolkina dupka (-542 m) and Banski Suhodol 9-11 (-401 m) are still under exploration and can surprise their explorers at any time.

  1. V. Popov: Zoning of the caves in NR Bulgaria, 1976. (in Bulgarian)
  2. I. Petrov: Sky of stone. M&F, 1977. (in Bulgarian)
  3. A. Jalov, S. Tsonev: Days and nights under the ground.  M&F, 1980. (in Bulgarian)
  4. A. Jalov, A. Taparkova-Pencheva, V. Peltekov, N. Genov, P. Nedkov, S. Gazdov, T. Daaliev: Bulgarians in the abysses of the world. M&F, 1986. (in Bulgarian)
  5. P. Beron, T. Daaliev, A. Jalov: Caves and Speleology in Bulgaria, Pensoft, 2006. ISBN 954642241X
  6. A. Jalov, Underground notebook. Sofia, 2005. (in Bulgarian)
  7. A. Addison, B. Osburn: Cartography and GIS Report 2006-2007 Mammoth Cave National Park, In: Cave Research Foundation 2006-2007 Annual Report, CAVE BOOKS, 2008, ISBN 978-0-939748-69-3
  8. Kiril Ivanov: The Abyss Snezhnaya, STENO, 2012. (in Bulgarian)
  9. J.A. Labegalini, A.A. Cigna, A.E. Romero, D. Ford, H. Trimmel, P. Forti, J. James, A. Eavis, K.S. Woo, C. Ek, P. Bosak, F. Nader, J.-P. Bartholeyns: Fifty years of the UIS. 1965–2015. Založba ZRC, 2015. ISBN 9612547858.
  10. S. Shanov, K. Kostov: Dynamic Tectonics and Karst. Cave and Karst Systems of the World, Springer, 2015. ISBN: 978-3662439913
  11. Lilia Ilieva: The First Tractate on Bulgarian History Found: Petar Bogdan, “On the Antiquity of the Father’s Land and on the Bulgarian Things”, Balkanic Forum ’18, No.1, 2018, pp. 98 – 103. ISSN 1310-3970.
  12. Website of Bulgarian Federation of Speleology
  13. UIS Bulletin
  14. Chronology of expeditions to the system “Snezhnaya – Mezhnogo”