Prohodna Cave – Eyes of God

Prohodna is one of the most famous caves in the karst region near the village of Karlukovo, Lukovit municipality. The geological phenomenon is 250 meters above sea level. The cave is easily accessible, just past the road from Lukovit to Karlukovo (2 km from the village), there is a road from Rumyantsevo village.

This is the longest cave tunnel in Bulgaria with a length of 365 meters and a height of the entrances 56 meters. As a result of the erosion caused by the permeating waters, the phenomenon “Okna” or “Eyes of God” was formed in the ceiling – two almost identical holes in the form of eyes. This gives the unique appearance of the cave. Looking down from below, they are very much like eyes that seem to be staring at visitors. The interior of the cave is dimly lit, as the displacement between the two entrances is great, and the daylight from the outside enters through them on bundles. The effect is astounding, especially in sunny weather.

The site is part of a cave corridor, whose direction is east to west. It was formed at the end of the Credit Period 66 to 68 million years ago. In the past, the waters of the Iskar River have filled the cave. Now the level of the river is below the cave floor. As a result of the active karst processes, characterized for this period, seismic activity and river activity, the cave-shaped cave corridor was interrupted and this part remained separate. Structurally, the cave consists mainly of light beige to white, healthy, massive organogenic limestones (there are well preserved fossils of shellfish, birch, bivalves, brachypods, gastropods, sea urchins and ammonites – more pronounced in the western part of the geological phenomenon). The thickness of the rock layers varies from 10 to 50 m.