Bungee jumpers jump over the Prohodna cave's entrance and tourists observe "The eyes of God", stone phenomen in the Prohodna cave near the village of Karlukovo, east of the Bulgarian capital Sofia, Sunday, June, 21, 2015. The two huge elongated holes in its ceiling look just like a pair of human eyes. And this impressive formation is rightfully named "The Eyes of God". Prohodna cave is a karst cave in north central Bulgaria, located in the Iskar Gorge near the village of Karlukovo in Lukovit Municipality, Lovech Province, some 150 km east from the bulgarian capital Sofia. Prohodna is the best known attraction in the Karlukovo Gorge, part of the Geological Park Iskar-Panega, one of the largest karst regions in Bulgaria and a popular location forspeleology. Formed during the Quaternary, Prohodna is 365 metres long, which makes it the longest cav (Photo by NurPhoto/NurPhoto via Getty Images)
