Until 1818, visitors were able to see only 300 meters from the cave network. Today it is more than 5 kilometers of tunnels, passageways and spectacular rooms that can be visited and admired by tourists.
The mains entrance is constituted by an artificially widened portion and others still in their natural state. The “Old signatures Gallery”, in which one can find traces left by visitors from the 13th century, is also located in the entrance. Our visit then starts on the platform of the railway of the cave, animated by a cheerfull crowd delighted to find here a little freshness, as the outdoor thermometer is currently showing 35°C!
The train of the cave takes us first through an artificial tunnel, then in a natural gallery whose blackened walls bear witness of the destruction of a fuel depot during World War II. Then we pass through two linked rooms, as the temperature drops rapidly. The first is studded with wonderful calcite concretions. The Gothic Room and the Hall of Congress (formerly known as the Dancing Hall) have formed for almost two centuries an exceptional setting for concerts and other events. The journey continues now in the midst of natural sculptures and transport us 2km further towards the Great Mountain, where we get off the train and reach our English-speaking guide.
The Great mountain (“Calvary”) is an underground room that was formed by the collapse of the ceiling, as evidenced by piles of stones and rocks all around us. In the ceiling, it is possible to observe the spot where the different layers of limestone collapsed. Water seeps through cracks and deposits in the form of calcite concretions on the ceiling. These are mostly small and young as they are crumbling, while the old colossal stalagmites of more than a million years old dot the ground. We climb to the top via a dimly lit road, and admire a particularly beautiful view, especially on the Russian Bridge where we will go.
After crossing it, we enter the Beautiful caves and the Russian gallery leading to the North and the point where the natural part of the Postojna cave ends. The end of the Beautiful caves is indeed connected to the Russian gallery with an artificial tunnel, which allows visitors to make a loop and pass under the Russian Bridge on the way back. The Beautiful caves are the most beautiful and richest of Postojna Cave and certainly the part that I like the most. In many places, they widen to form rooms whose names evoke the characteristics of the concretions they shelter.
One is the Room of Fistulas in which thin calcite tubes, white and transparent, are hanging from the ceiling next to each other. The ceiling of this room may look like a stone rain, and some guides even have nicknamed it the “Spaghetti Room”.
The White Room is named after the extremely white and pure calcite concretions, which contains only very few other mixed elements. This room also contains very characteristical volcanic lakes. Some of them reach an exceptional size and form pools that hold thousands of liters of water.
With slightly less calcite than the previous two cavities, the Red Room (no reference to Shining!) is dominated by a red calcite. The color of the calcite depends of the elements carried by the water from the surface or through the rock above the cave, which are precipitated together with the calcite. The red color is due to the iron or clay particles, while black color is from manganese, carbon or dark colored substances in the ground.