Prehistoric cave paintings are extremely rare south-east of the Alps, but in 2009 a scientist stumbled upon mysterious red and black lines and dots inside a little-known cave in the south-west of the country in the first such discovery in Slovenia.

A total of 32 red ochre lines, signs or symbols of various sizes and another 28 black dots and lines made with charcoal are hidden deep in Bestažovca Cave, near Sežana. They are believed to be at least 7,000 years old.

They were discovered in January 2009 when Andrej Mihevc from the ZRC SAZU Karst Research Institute visited this hard-to-access cave with professional cave explorer Bojan Volk to take photos for his presentation.

Volk spotted the drawings and Mihevc immediately knew what was in front of them, as the cave had been an archaeological site before. Local cave explorers rediscovered Bestažovca in the 1970s, and in the following years several fragments of pottery and bones would be found there.

Research so far has shown that the drawings are from Neolithic, the period when hunters-gatherers slowly became farmers, but they could be much older.

They have been preserved because one of the two entrances to the cave became sealed with gravel some 7,000 years ago, resulting in a stable climate.

Once sealed at Perkova Pečina, the cave became practically inaccessible at the other entrance - Bestažovca, where entry is possible through a 25-metre pit.

The fact that the main entrance was closed is important in dating the drawings, archaeologist Anton Velušček, head of the ZRC SAZU Institute of Archaeology, has told the STA.

"Radiocarbon dating of the charcoal from the cave shows this part of Bestažovca was accessible until about 7,000 years ago, and the radiometric dating of the charcoal supports the dating of the archaeological finds.

"Therefore, archaeologists assume the drawings are probably of the same age, but may be older. Typologically, they could be placed in the Palaeolithic period, and equally in the Neolithic period. But they are not younger, as we don't have a single archaeological find to indicate that man was present in the cave later," he says.

Researcher Mihevc wrote extensively about the cave's geological development and drawings in Arheološki Vestnik, the country's main journal for archaeology, in 2022.

Apart from discovering the drawings, he also found pieces of charcoal, remains of charred torch, grass laid in a wreath around a stalagmite, and herbs.

Based on the finds, he believes the cave might have been used as a shrine. As he wrote in his 2022 paper, Bestažovca "may represent the earliest known sanctuary in Slovenia".

Bestažovca is not the only cave in Slovenia to hold prehistoric drawings. Traces of a small red drawing were also discovered in Partizanska Cave in 2008.

However, since this discovery did not come to light before 2015 in a paper in the journal Annales, Bestažovca is considered the first discovery of this kind in the country.

The authors of the Annales paper suggested that this could be "the first Palaeolithic cave painting art in Slovenia".

Cave art from Bestažovca and Partizanska may not be groundbreaking on a global scale, but is extremely important for Slovenia and the wider area south-east of the Alps, where such finds are extremely rare.

"They show that there are prehistoric drawings in our country, that there are many more than archaeologists had assumed," Velušček says.

"At the same time, they show that we need to look for them in caves that were, of course, once inhabited and that are not filled with young sediments."

After further research and sounding was carried out in 2010 and 2011, Velušček and Alma Bavdek, an archaeologist from the Postojna regional museum, are currently working on a paper on the archaeological finds from Bestažovca.

Bavdek included Bestažovca in the permanent exhibition on karst at the Notranjska Museum in Postojna, the town known as the world's capital of karst research.

With the cave closed to the general public, the Postojna museum is the only place where history buffs can get a glimpse of "the Slovenian cave art".

What is displayed at the museum is "perhaps the most expressive image, perhaps a kind of stylised man", she says about a 31-centimetre vertical red line, split on one side, with three smaller lines on the left and right.

Also on show at the museum are some other finds from Bestažovca, such as an axe made of jade and several pieces of pottery.