Temnata Dupka is the longest Staroplaninska cave (5300 m) and the third longest in Bulgaria. It is located in a rocky cliff above Lakatnik, 27 m above the level of the Iskar River, on the southeastern slope of the Koznitsa ridge, which is part of the Western Stara Planina.
The path to the cave starts well-marked from the asphalt road, near the Cave restaurant. It is well fenced with railings and has benches and gazebos where you can rest along the way. It is a gentle climb lasting no more than ten minutes. But the cave itself is not available for casual visits, as it is only suitable for experienced speleologists. But if you do decide to take a peek inside, bring a headlamp and comfortable shoes as it's dark and the floor is littered with rocks. It is highly recommended to be accompanied by an experienced speleologist who knows the labyrinth of the cave well.
The cave consists of two galleries interconnected in a complex maze of entrances, galleries, multicolored (reddish and brown) cave formations, waterfalls, siphons and other stunning rock formations. It is famous for its underground lakes, many of which are up to 3 m deep. The deepest, called "Pepi", is no less than 12 meters deep. Another, called by the diggers "Zhekov lake", springs an underground river that flows along the lowest floor of the cave and flows through the Zhitolyub karst spring, emerging as a beautiful cascade at the foot of the Cave Restaurant. The flow rate of Zhitolyub can reach 1200 liters per second during heavy rain.
Do not drink from the water as it is most likely contaminated - in 1983 it caused a hepatitis epidemic! The name Zhitolyub is associated with the water mills, which in the past used their power to serve the nearby villages.
Temnata Dupka Cave is among the first explored and mapped caves in the country – the first known visit dates back to 1912, when Prof. Ivan Bures studied its bats and other fauna. Surveys, including the preparation of an accurate map, continue to this day. Temnata Dupka is a system of two main connected galleries. The ambient temperature is + 11 / + 14 ° C.
The cave has been a natural landmark since 1962 and falls within the territory of the "Vrachanska Planina" nature park.