Prohodna is a karst cave in Bulgaria, located in the Iskar Gorge near the village of Karlukovo in Lovech Province. Prohodna is the best known attraction in the Karlukovo Gorge. The cave is known for the two eye-like holes in its ceiling, known as the Eyes of God or Oknata. The cave has two entrances which lie opposite one another, known respectively as the Small Entrance and the Big Entrance. Prohodna is most notable for the two equal-sized holes in the ceiling of its middle chamber. The holes, formed through erosion, let in light into the cave.