"Postojnska jama" cave

virtual excursion (2012)

year 2005

year 1999/2000

24,120 meters of subterranean tunnels of the Postojnska jama cave system have been explored until the year 2022. This karst cave system with a maximum documented depth of 115 meters near Postojna is the second-longest in Slovenia after the M16 system - Tolmiski Migovec, which has a length of underground tunnels of 43,009 meters and the largest tourist cave on the Dinaric Karst.

The cave system of Postonjska jama also includes its natural and historical entrances: Otoška jama, Magdalena jama, Črna jama and jama Pivka. The cave was created by a subteranean river Pivka, which sinks from the Postojna polje under the hill Sovič and continues its underground flow towards the underground confluence with the river Rak in the Planina jama cave. From the Planinska jama cave, it flows to the plain as the river Unica.

After the Pivka river made its way underground, it gradually lowered its bed over the course of two million years, creating different levels of the cave. The water that seeped through the bejeweled surface deposited calcite drop by drop in the dry tunnels from the dissolved limestone, creating unique stalactite forms.

The constant temperature inside the cave three decades ago was about 8 °C, but today it varies between 8 and 10 °C, which is a result of global climate change.

Postonjska jama cave is famous nowadays as the cradle of speleobiology, that is, the biological science of the life of animals in subterranean. The most famous is the Olm (Proteus anguinus).
In 1797, Josip Jeršinovič the noble Löwengreif discovered it in Črna jama, one of the entrances to Postonjska jama. In 2016, in Postonjska jama, as the first touristic cave in the world, the reproduction of a human fish in captivity was successful.
In 1831, the first cave beetle was discovered in Postonjska jama, "Dobrovratnik" (the small-necked beetle, scientific name Leptodirus hochenwarti). Until then, it was believed that there was no life in caves. The discovery of Dobrovratnik beetle encouraged naturalists to continue research, and many new specimens of cave animals were subsequently found in Postonjska jama.

To date, more than 175 species of animals living in the Postojnska jama -Planinska jama cave system have been listed in biological literature; of these, 115 are true cave species, which is the largest in the world and shows the great biodiversity of the local karst subsoil. Many representatives of several groups of cave animals were described for the first time based on specimens from Postonjska jama. Therefore, in the cave section "Trenches of new signatures", 50 meters from the main entrance to the Postonjska jama, a modern speleological station interesting for visitors has been restored: Vivarij Proteus. On the initiative of Ivan Andrej Perek, this station was founded 100 years after the discovery of the small-necked speleothem, in 1931 as "Stazione biospeleologica". It was one of the first such laboratories in the world and was modernly equipped for those times.

The preserved signatures on the cave walls bear witness to the fact that Postojska jama was visited long ago. The oldest of them date back to the 13th century.

Organized tourist development began after 1818, when local man Luka Čeč discovered the inner parts of the Postojnska jama. Already in 1819, the first routes were arranged in it. They established the Cave Commission, which took care of the cave and established the first cave guide service. In 1884, electric arc lighting was introduced in the cave, which was among the first in the world. Walking through the cave was tiring, so already in 1872 railway tracks were laid all the way to the foot of Velika Gora, along which the cave guides initially pushed carts with visitors. Today, trains are powered by smaller electric locomotives.

In 1928, the "Cave Palace", a monumental reception center for visitors, was built in front of the entrance to the Postojnska jama, which even today combines the interior of the cave with everything that a modern guest needs outside it.

More than 5 km of caves are open for regular tou

Postojna Cave is one of the most extensive and thoroughly explored cave systems in Slovenia. To date, 24,120 meters of underground passages have been surveyed, making it the second‑longest cave system in the country, surpassed only by the M16–Tolminski Migovec system, which exceeds 43 kilometers of passages. The maximum documented depth of the Postojna system is 115 meters. It is also the largest show cave of the Dinaric Karst and one of the most visited karst attractions in the world.

The Postojna Cave system includes several natural historical entrances: Otoška Cave, Magdalena Cave, Črna Cave, and Pivka Cave. The entire system was carved by the sinking river Pivka, which disappears beneath the hill of Sovič after crossing the Postojna Karst Field and continues its subterranean journey toward its confluence with the Rak River in Planinska jama. From Planinska jama, it emerges as the Unica River, one of the seven names of the Ljubljanica.

When the Pivka River began to penetrate the underground around two million years ago, it gradually lowered its bed and created a multi‑level cave system. The oldest passages are now dry, while the younger ones remain active. Water seeping through the karstified surface deposited calcite drop by drop over thousands of years, forming the cave’s rich speleothem world: stalactites, stalagmites, draperies, rimstone pools, and other formations that have become the cave’s signature.

The temperature inside the cave has changed over recent decades. While it remained stable at around 8 °C throughout the 20th century, it now ranges between 8 and 10 °C, a shift attributed to global climate change and increased visitor numbers.

Postojna Cave is internationally recognized as the birthplace of speleobiology. In 1797, the cave’s most iconic inhabitant—the olm (Proteus anguinus)—was discovered in Črna Cave. In 2016, Postojna Cave became the first show cave in the world to successfully breed olms in captivity, a milestone in subterranean biology.

In 1831, the first known cave beetle, Leptodirus hochenwarti, was discovered in Postojna Cave. This discovery revolutionized scientific understanding of cave life—until then, it was widely believed that caves were devoid of animals.

Today, the Postojna–Planina cave system is known to host over 175 animal species, including 115 true troglobionts, the highest number recorded in any single cave system worldwide. Many species were first described from specimens collected in Postojna Cave.

Just 50 meters from the main entrance lies the modern speleobiological station Vivarium Proteus Cave, located in the “New Signatures Passage.” It is the successor to the pioneering Stazione biospeleologica, founded in 1931 at the initiative of Ivan Andrej Perko—one of the first biospeleological laboratories in the world.

The oldest signatures on the cave walls date back to the 13th century, proving that people visited Postojna Cave long before organized tourism.

Modern tourism began in 1818, when local Luka Čeč discovered the inner parts of the cave. By 1819, the first pathways were built, and the Cave Commission was established to manage the cave and organize the first guide service.

In 1872, railway tracks were laid inside the cave, allowing guides to push visitor carts. In 1884, Postojna Cave introduced electric lighting, one of the earliest underground installations of its kind. Today, visitors travel by electric cave train.

In 1928, the monumental Jamski dvorec (Cave Mansion) was built at the entrance, serving as the main reception center.

More than 5 kilometers of the cave are open to visitors. Each year, around 700,000 people visit Postojna Cave, and over its two‑hundred‑year history, it has welcomed more than 40 million visitors, making it one of the most visited tourist attractions in Europe and the world.

During the Second World War, German forces stored fuel inside the cave near today’s train exit to protect it from air raids. Although heavily guarded, a sabotage unit of the Vojkova Brigade managed to infiltrate the cave on 23 April 1944 through an old, partially collapsed artificial tunnel from Črna Cave—one not marked on German maps. They blew up the fuel depot, causing a fire that burned for a week. The soot from the explosion still darkens the cave walls today.

Postojna Cave has been an important part of my research and documentary work. I first documented the entire cave system in 1999, creating a comprehensive visual record of its passages and chambers. My most recent full documentation was completed in 2012, using more advanced techniques to update and expand the visual archive. Both projects required months of fieldwork and offered a rare opportunity to experience the cave beyond the tourist paths, in its full geological and biological complexity.

rist visits. Visitors can walk through them accompanied by cave guides or with an audio guide in one of the world's languages.

Around 700,000 visitors visit the Postonjska jama every year. With more than 40 million visitors from all over the world, it is one of the most visited tourist attractions in Europe and the world in its two-hundred-year history.

During World War II, the German army stored fuel for the entire northern Adriatic, from Trst to Rijeka, in the cave, at today's exit from the tourist train and the exit from the cave, to protect it from air attack. The entrance to the cave warehouse was, of course, heavily guarded, but on April 23, 1944, a sabotage platoon of Vojka's brigade managed to sneak into the Postonjska jama and blow up the warehouse. For this purpose, partisan saboteurs used an old, artificially made tunnel that led to Postonjska jama from Črna Jama. The trench was half-filled and was not marked on the German maps of the cave.

The fire burned for a week. It caused the stalactites to fall, the walls of the cave covered with soot. The black layer of soot is still visible in this part of the cave today.

Literature:
Kataster jam, URL: https://www.katasterjam.si, cited July 10, 2022;
Skoberne, Peter One hundred natural sights of Slovenia (Slovenian language, Ljubljana, Prešernova družba, 1988;