The Eyes of God (Prohodna) Cave in Karlukovo Bulgaria.

Located in the Iskar Gorge amidst one of Bulgaria’s largest karst regions, Prohodna is one of the best-known caves in a country full of them. This is thanks in large part to the eerily symmetrical holes in the cave’s ceiling, which provide visitors with a rather striking subterranean image.

Prohodna itself has two entrances opposite each other — the “Small Entrance”, which is 35 meters high, and the “Big Entrance”, which is 45 meters high — making it the largest cave passage in Bulgaria (its name, in fact, means “Thoroughfare Cave” or “Passage Cave”).

 The pools of light permitted by the ceiling holes can sometimes be visible from either entrance, creating the appearance of glowing eyes staring out from the dark depths of the cave. Little surprise, then, that they are known locally as both the Eyes of God and the Eyes of the Devil. These unique formations provided the backdrop for a scene in the 1988 Bulgarian movie Time of Violence.Known as the Eyes of God, these holes are located in the middle chamber of the 262-meter-long cave, illuminating the interior and providing a uniquely framed view of the firmament above. Remarkably in size, similar in shape, and eyeish in appearance, these holes are the result of natural erosive forces. (The possibility of human embellishment has not been ruled out). These slow and steady forces are still at work, as is often demonstrated by the water running down the cave walls from the “crying” eyes above.

Prohodna shows evidence of prehistoric habitation, though whether it was a domestic or ritual site is unclear. Today, the Big Entrance of Prohodna is a popular location for bungee jumping.