A fantastic web of tunnels, passages, galleries and halls, the astonishing diversity of Karst features as well as easy access are certainly the main reasons for such popularity of the cave and a large number of visitors, which has already reached 38 million in 200 years.
image credit: https://www.postojnska-jama.eu
Postojna Cave was carved by the Pivka River over millions of years. There are stalagmites, stalactites, and formations called curtains or draperies that look like folded curtains. The cave system is 24 km long and is made up of four caves interconnected through the same underground river. However, according to speleology rules, the passages and siphons connecting the caves must be walked or swum through by man for them to be considered one whole. Connecting two of the main cave systems will make this the longest cave system in Slovenia and one of the longest in all of Europe. There remain 400 meters between the two caves, which would make the cave system between 31,000 meters and 35,000 meters long.
The caves are also home to the endemic olm, the largest troglodytic amphibian in the world. The tour through the caves includes an aquarium with some olms in it. On January 30, 2016, a female olm at the cave began to lay over 50 eggs. The olm (Proteus anguinus) has always excited people's imagination. Initially, it was believed it was the dragon's offspring brought onto the surface by high waters.
images credit: https://www.postojnska-jama.eu
For many years, visitors were able to explore the cave only on foot. In the spring of 1857, when the cave was visited by the imperial couple, three velvet sedan chairs were made for Empress Elisabeth and her ladies-in-waiting. In 1872, the tracks were laid all the way to the Great mountain (at the time known as the Calvary), giving visitors the option of a ride in two-seater carriages, which were pushed by the cave guides. Although the idea of introducing machines instead of man-power was present even prior to World War1, it was not realised until 1924, while the year before the entire railway system inside the cave was overhauled.
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