Temnata Dupka is the longest Stara Planina (Old Mountain) cave (5300 m) and the third longest in Bulgaria. It is located in a rock escarpment above Lakatnik, 27 m above the Iskar River level, on the south-eastern slope of the Koznitsa Ridge, which is part of the Western Old Mountain Range.
The path to the cave starts well marked from the asphalt road, near the Peshterata (Cave) restaurant. It is well framed with railings, and has benches and gazebos where you can take breaks along the way. It is an easy ascent lasting no more than ten minutes. But the cave itself has not been made available for casual visits, being only suited for experienced spelunkers. But if you still decide to have a peek inside, wear head lamps and comfortable shoes, as it is dark and the floor is littered with stones. It is strongly recommended that you are accompanied by an experienced spelunker who knows well the cave's maze.
The cave consists of two galleries connected to each other in a complex labyrinth of entrances, galleries, multicoloured (reddish and brown) cave formations, waterfalls, siphons and other stunning rock formations. It is known for its underground lakes, many of which are up to 3 m deep. The deepest one, named "Pepi", is no less than 12 m deep. Another one, called "Zhekovo Lake" by potholers, siphons out an underground river, which streams along the lowest cave floor and flows out through the Zhytolyub karst spring, emerging as a beautiful cascade at the foot of the Cave Restaurant. Zhytolyub's outflow rate could reach 1200 litters per second during heavy rain.
Do not drink from the water as it is most likely contaminated - in 1983 it triggered a hepatitis epidemic! The name Zhytolyub is associated with the water mills that used its power in the past to service the nearby villages.
The Dark Hole was among the first caves in the country to be explored and mapped - the first known visit dates back to 1912, when Professor Ivan Buresh studied its bats and other fauna. The explorations, including the making of an accurate map, have continued even to this day. Temnata Dupka is a system of two main interconnected galleries. Its ambient temperature is + 11 / + 14 ° C.
The cave has been a natural landmark since 1962 and falls within the territory of the Vratsa Mountain Nature Park.
Temnata Dupka is 59 km away from the city of Sofia, on the road Sofia-Svoge-Mezdra going through the Iskar Gorge.
Access to the cave is free of charge, but not recommended: the cave is neither equipped with lighting nor suitable for casual visitors. Only the trail that goes to its entrance is well-marked and secure. The cave restaurant preferred by the guests of the area is just under the actual cave.