Pekel Cave is one of the most distinctive karst features of the Ponikva Karst, situated in a 600-metre-long blind valley on its southern edge. It lies approximately four kilometres north of Šempeter in the Savinja Valley, in a landscape where the surface gradually transitions into an underground karst system. This transition is key to the cave’s formation: over thousands of years, the water of the Ponikvica stream widened fractures in the limestone, deepened channels, and carved out the passages that today form the main part of the cave system.
Geographical Setting and Geological Structure
The entrance to the cave is located at the very end of the valley, where the relief closes and descends into the subterranean world. The cave is developed in limestone, a rock highly susceptible to dissolution, making it ideal for the formation of karst features. For this reason, Pekel Cave is an excellent example of a system shaped by a combination of erosion, corrosion, and continuous water flow. One of its most recognisable geomorphological elements is a roughly four-metre-high waterfall over which the Ponikvica drops into the upper part of the cave — a natural feature that vividly illustrates the dynamics of both past and present water activity.
Two-Level Cave System
Pekel Cave is developed on two levels, a characteristic typical of caves where watercourses have gradually deepened over time. The upper level is now dry, without a permanent water flow, while the lower level follows the active course of the Ponikvica. The tourist path leads through both levels, and the exit is arranged through an artificial tunnel that enables a circular route and reduces the impact of visitors on the cave’s sensitive natural structures.
Discovery and Tourist Development
Although the cave was known to locals as early as the late 19th century, systematic tourist development began only in the 1970s. At that time, walkways, stairs, and lighting were installed, and the cave was reopened to the public. Since then, Pekel Cave has been a constant part of the local tourist offer and an important natural landmark of the Ponikva Karst.
Cave Features and Microclimate
Inside the cave, visitors encounter numerous karst formations: erosion channels, speleothems, rimstone pools, and sediment deposits that reflect changing water conditions over time. The lower level, where the Ponikvica still flows, remains geomorphologically active — the water continues to reshape passages, deposit sediments, and create new microforms. The cave’s microclimate is stable, with constant temperature and high humidity, typical of underground spaces in this region of Slovenia.
Significance of Pekel Cave
Pekel Cave brings together the geographical, geological, hydrological, and historical characteristics of the Ponikva Karst. Its location, two-level structure, active watercourse, and early recognition among visitors place it among the most important natural features of the Savinja Valley. It is an outstanding example of a living karst system, offering insight into the dynamics of underground processes and the richness of Slovenia’s karst landscapes.