Prohodna, in bulgarian Проходна, is one of the best known caves in Bulgaria, a country full of caves, and is located in the Iskar Gorge, one of largest karst regions, 2 km away from Karlukovo Village and 112 km away from Sofia.
If it’s so famous, is especially thanks to the strange symmetrical holes in the cave’s ceiling, which offers a rather striking subterranean image. Known as “the Eyes of God”, these holes are located in the middle chamber of the cave, long 262 meter, illuminating the interior and providing a beautiful framed view of the sky above. On a sunny day, as you approach the entrance, you are greeted with two shining eyes seeing at you from the darkness of the cave.
These holes are probably the result of natural erosive forces, but there is no unanimous opinion on whether this is a natural phenomenon or a result of human activity. These natural slow and steady forces are still at work, and an example is often demonstrated by the water running down the cave walls from the crying eyes above. Seen from a specific angle, they even resemble a face that looks down, and in fact when it rain it seems as if they are “crying”. In my opinion, there were simply natural holes which seemed two eyes and probably then shaped by someone.
The Prohodna caves have two entrances opposite each other, the Small Entrance which is 35 meters high, and the Big Entrance, which is 45 meters high, and is the biggest cave arch in Bulgaria (its name, in fact, means “Thoroughfare Cave” or “Passage Cave”). The pools of light that came by the ceiling holes can sometimes be visible from either entrance, creating the sensation of glowing eyes from the dark depths of the cave. And in fact they are known like the Eyes of God (or Eyes of the Devil, for some local people).
This location was the frame for a scene in the Bulgarian movie of 1988 “Time of Violence”. Bungee jumping are practiced from the big entrance, and Prohodna Cave is a popular destination also for climbers. There are sport climbing routes divided into several sectors, and despite there are a variety of level of difficulty, they are considered to be some of the hardest in Bulgaria.
Archaeological material found in this caves testifies that humans used this cave system since the Upper Paleolithic time, but it’s not clear if was a domestic or ritual site. On 21th March, the day of the Spring Equinox, the light passing through the holes shines on an alcove filled with water, and this is suggestions that the cave might have been used for religious ceremonies related to the beginning of the spring.