Postojna Cave - world-famous baroque cave home to baby dragons

"Postojna Cave is compared to baroque or rococo in terms of arts, because it is colourful and has all the different dripstone forms... Other caves have a more Gothic style, they are tall but lack the finesse," tourism company Postojnska jama CEO Marjan Batagelj told the STA.

To add to the prestige, the cave boasts the Concert Hall, known for its exceptional acoustics, which has hosted a number of events such as musical and theatre shows.

The cave was first described in the 17th century by polymath Janez Vajkard Valvasor. In 1818, a local, Luka Čeč, discovered a large inner area of the cave that the then heir to the throne Ferdinand I of Austria visited just a year later.

"The extraordinary natural heritage was compelling already then... Virtually everybody who wanted to be somebody in the 19th century and travelled around Europe made a stop in Postojna," explained Batagelj, who is also a karstologist.

Since then, more than 150 world leaders have come to visit, including Austro-Hungarian Emperor Franz Joseph I and Empress Elizabeth, who were the first to sign the Golden Book of visitors in 1856.

It was also a go-to destination for former Yugoslav leader Josip Broz - Tito, who visited the cave with Nikita Khrushchev and Jawaharlal Nehru, among others. More recently, the likes of Vaclav Havel and the Prince and Princess of Akishino of Japan came to marvel in its splendour.

Due to its popularity the cave was fitted with electric lighting as early as 1883, preceding the capital Ljubljana and, according to Batagelj, even London. "The cave is timeless, it mixes the newest technologies and the things nature has created over millions of years - drop by drop."

A mini railway was introduced in the cave 140 years ago and now carries up to several thousand visitors per day on a journey which includes a walk that reveals "the most beautiful corners of the underground world".

However, natural beauty is not the cave's sole claim to fame. It is also the cradle of speleobiology, being home to over 120 species of animals, including the baby dragon or olm, an aquatic salamander.

The olm is endemic to extensive underground water networks of the limestone karst spanning from southern Slovenia to Bosnia. Due to its skin colour similar to that of Caucasians, people in the region call it the human fish.

It was again Valvasor who first described the secretive creature in 1689. He said that olms used to wash up after heavy rains and locals believed at the time that they were the offspring of cave dragons - hence the name baby dragons.

And there may be more secrets beneath the surface. Batagelj noted that the system - some 24 kilometres of passageways have been discovered so far - could still hide unknown caves.

Indeed, the unknown underground areas present Slovenia with the possibility of being promoted as the only country in the world for which the area cannot be determined precisely because of its "two storeys".