Prohodna Cave is located in the Karlukovo Gorge, Lukovit municipality, Lovech district. This is one of the largest karst (limestone) regions in Bulgaria particularly attractive to speleologists. In 2006 the area was declared a geopark.
Prohodna lies about 2km from the village of Karlukovo situated 120km northeast of Sofia, on the road to the town of Pleven. It is among the best-known caves in the area and has the longest tunnel in Bulgaria – 262m. Its arch is 47m high. The cave occupies an area of 10 000 sq m.
A noteworthy attraction of the cave is a formation known as God’s Eyes ( Okna). It consists of two eye-shaped holes, almost equal in size. They were formed through erosion that hollowed out the ceiling. The holes are in the middle hall and provide natural light to the cave. The light has a yellowish-green hue because of the rocks.
Some well-known Bulgarian and foreign movies have been shot in the cave, e.g. Time of Parting. The place is also good for bungee jumps, rock climbing and water journeys.
Prohodna was declared a natural sight in 1962.
Close by is the Zadunen Dol ( Blind Glen|) canyon, other caves, beautiful meanders, rock arches and rock monasteries dating from the 13th and 14th century.