Before electric lights were set up inside Postojna Cave, illumination had been provided by cave guides by means of oil lamps and by cave lamplighters who lit up and put out candles on the wall as they went along. The amount of lighting provided depended on the fee visitors paid for their tour. They could choose between a few candles only or "lighting on a grand scale" for which four to five kilograms of candles were used.

Electric lighting was temporarily installed in Postojna Cave in 1883 at the time of the visit from Emperor Franz Joseph. Three electric lights lit up the Great Hall. A year after, electric lighting was installed inside the cave as a whole and Postojna Cave was thus illuminated by means of electricity for a whole three years before London.

Cave Committee chaired by Anton Globočnik became interested in electric lightining in1878. He wrote in his Chronicle at the time: "Electrical wiring has become a reality. On 24 May 1884, installation was completed and the cave was illuminated during a visit from students of the Rijeka Naval Academy. This was a tremendous success. When the lights were turned on, the splendours of stalactites and stalagmites that had never been seen before appeared in front of our eyes. Twelve arc lamps, each with the power of 1,400 candles, illuminated the six most prominent spots in the cave: the Great Hall, the Dance Hall, the Laundry, the Crossroads at the Grave, Belvedere and Calvary".

At the beginning electricity was generated by a steam locomotive, which was temporarily accommodated in a wooden shack not far from the entrance to the cave. It was delivered a mere few days before the  Franz Joseph arrival in 1883. Besides the electricity, the cave was additionally illuminated by 16,000 candles and adorned by 6 00 colour balloons.

Postojna Cave thus became one of the first places in the then Duchy of Carniola to have electric lighting and at the same time also featured one of the first subterranean illuminations in the world.