在地質學上通用的喀斯特 (Karst) 一詞，意指石灰岩與水的交互溶蝕作用，形成了溶洞、伏流、石灰阱、岩溝及灰岩盆地等繁複地形。而 Karst 即源自斯洛維尼亞文的 Kras，指的就是斯洛維尼亞西南部這塊與義大利交界的特殊地形地貌。在這一整區的喀斯特地形中，又以200萬年前，由皮夫卡河 (Pivka) 溶蝕而成的波斯托伊納溶洞 (Postojnska Jama) 最大也最為著名 。
What Makes the Postojna Cave so Special?
(1) The only cave with a double track railway
For 140 years, the Postojna Cave, as the only cave in the world, offers a unique and adventurous ride with a special train. From 300 meters of accessible routes in 1818, a visitor today can enjoy the tour of 5 km through tunnels and passages which takes about an hour and a half. The tour begins at the entrance platform of this unique cave railway, where 3.7 km long railway tracks begin. The visitors can see one part of a scenic underground maze from the train, and then enjoy the second part on foot and admire playful stalactite forms in no hurry. p.s. On 17 August 1819, the first visitor to walk through the newly discovered part of the cave was the Austrian Crown Prince Ferdinand I. For many years visitors could only explore the cave on foot. On 16 June 1872 the first tracks, with a total length of 2260 meters, which led to the Great Mountain (previously known as Calvary) were laid. These enabled transport of little two-seater carriages which were pushed by the cave guides. However, the small man-powered railway could not cope with the large numbers of visitors. The idea of introducing machines instead of man-power was planned during the WWI; however, it was only realized in 1924. On June 20, 1964, there was a formal opening of the two-track line with a loop near the entrance to the cave and a terminus at the end of the line on the foot of the Great Mountain, known as the Calvary station. In 1968, the second stage was completed with the construction of the loop to the Concert Hall. The two-track loop line enabled uninterrupted transport of numerous visitors, who visited the cave in the following decades.
(2) Stalactite paradise on every corner
21 km of passages, galleries and magnificent halls offer a unique experience of the underground world.
The Old Cave: The old cave is the part of the cave which was discovered in 1818. It was on the route visitors were guided on in the early days of cave tours. This is where the cave railway mostly runs today and parts of the old footpath are still preserved. The part that stands out most is the Congress Hall, where magnificent festivities used to be organized. Not far away from the Congress Hall, on the left side of the track, there used to be a small building which housed an underground post office. It was set up in 1899 and used to operate on this spot until 1927, when it was moved further into the cave.
The Congress HallThe Congress Hall got its name after the World Speleological Congress which was held here in 1965. Prior to that, it was called the Ballroom hall due to the Whitsuntide Festival which was celebrated here soon after its opening. According to the cave archive, the first festival was organized in 1825. On that day, the cave and the Ballroom in particular were festively illuminated and the dance accompanied with music was organized.
The Great Mountain: The great mountain is an underground hall formed due to the collapse of the ceiling, proof of which is a mound of collapse rocks and debris. The ceiling reveals precisely where individual limestone layers collapsed. On account of crumbling, the stalactites are smaller and younger, while the ground is covered in giant stalagmites over half a million years old.
Located at the foothills of the Great Mountain there is the exit station of the cave railway, where visitors leave the train and continue the tour on foot.
The Beautiful Caves and the Russian Passage: The Beautiful caves and the Russian passage are passages leading to the north where the natural part of the Postojna Cave ends. The end of the Beautiful Caves is namely linked to the Russian passage with an artificial tunnel, so visitors do not have to return along the same route and come back under the Russian Bridge. The Beautiful Caves are the most magnificent and strongly calcified part of the Postojna Cave, which in some places extends into halls named after the characteristics of flowstone.
The next hall is called The Red Room due to its reddish color of the flowstone. p.s.The color of the flowstone depends on the admixtures brought into the cave by water or from a rock formation above the cave and is deposited there together with the calcite. Water usually turns red because of admixtures of iron and clay, while manganese, carbon or dark soil makes it black.
From underneath the Russian Bridge the route continues towards the Concert Hall. On the left-hand side in a widening of the passage, visitors can catch sight of the best known symbol of the Postojna Cave, a calcite column with beautiful grooves and next to it a 5-metre high shiny white stalagmite called The Brilliant. The Brilliant stands in a spot with a strong and even drip from the ceiling. A thin layer of pure calcite sinter is deposited constantly and evenly by the water trickling down the rounded crown of the stalagmite. That is why it looks so extremely white and shiny, and it is not surprising that it has been the symbol of Postojna Cave and the Slovenian Karst for decades. A pillar stands next to it in true baroque splendor.
p.s.The creator of all these wonders is sinter, a mineral, usually calcite, deposited by supersaturated water. Sinter builds stalagmites, wall linings, pools, crusts and other fantastic forms in karst caves.
In the background of the Brilliant, the walls of the hall flaunt sinter curtains and a sinter fountain called The Organ, with tiny stalactites hanging from the ceiling. This is definitely one of the beautiful sights in the sinter-rich part of Postojna Cave.
The Concert Hall: The concert hall is one of the largest halls in the Postojna Cave and can accommodate several thousand people at a time. Concerts have been organized in the hall for over a hundred years and the venue is still very popular, which is understandable its uniqueness creates an amazing atmosphere for special events.
The visitors may here wander around for some time, buy souvenirs and then heads towards the cave railway stop in the passage below the Concert Hall and exit the cave by train.
(3) Meet the dragon’s offspring
The unusual looks of the olm have always sparked our imagination. At first it was believed that they were just baby dragons which the high tide brought to the surface. As a matter of fact, there might be some truth to these old beliefs.
The human fish or olm (Proteus Anguinus) is a neotenic animal. In simple words, this means that an adult keeps most of its juvenile features. The Proteus is 25-30cm long and is the biggest cave-dwelling animal in the world. It’s a blind amphibian and belongs to the ancient family Proteidae. The olm feeds on small crabs, worms, snails and other water invertebrates. It can survive up to 10 years without food and it can live up to 100 years. In Slovenia the Proteus is protected by legislation. In 1982 it was placed on a list of rare and endangered species.
(4) A tourist attraction for 200 years
Electricity: Before electric lights lit up the cave, it was illuminated by cave guides with oil lamps and by cave lamplighters who lit up and put out candles on the wall as they went along. The scale of the lighting depended on the fee the visitors paid for a tour. The guest could choose between a few candles or “big lighting" for which four to five kilograms of candles were needed. Electric lighting, the first in the province of Carniola, was temporarily arranged in 1883 during a visit from Emperor Franz Joseph. The next year, Postojna Cave became the third cave in the world to have permanent electric lighting (a year earlier electric lighting was set up in the Kraushöhle cave in Austrian Styria and even earlier, in 1881, in Luray Caverns, USA).
The oldest underground post office: Postojna Cave and the Pošta Slovenije postal service have an interesting common history of 112 years. They can boast the oldest underground post office in the world. In 1899, a small facility was built at the Congress Hall to provide post office services. According to the information available, this is the oldest underground post office in the world; it was entered in the list of post offices by the world postal association and the Austrian post in 1901. Today, the Concert Hall houses an exhibition of the 112-year history of the underground post office. Visitors can buy postcards and special stamps with motifs from Postojna Cave. One of the postcards available features a photograph of the world’s first underground post office, which was published in a Viennese newspaper in 1911.