Kolkinata Dupka Cave is officially the deepest and the longest cave system in Bulgaria. This underground marvel stands as the Holy Grail of Bulgarian speleology, drawing researchers, cavers, and scientists from all over the globe. The cave is nestled in the karst landscape of the Ponor Mountain (part of the Western Balkan Mountains), located in immediate proximity to the scenic village of Zimevitsa within the Svoge Municipality. Official exploration and organized expeditions into this massive subterranean labyrinth began back in 1963. Over the decades, the cave has consistently amazed scientists with its sheer scale. The interior of Kolkinata Dupka conceals a raw and breathtaking underground world. Its complex galleries are traversed by several subterranean rivers, forming crystal-clear lakes, steep cascades, and stunningly beautiful waterfalls surrounded by colossal, echoing halls. Official Geographical Parameters and Records: - Status: The longest and deepest explored cave in Bulgaria (National Record). - Location: Zimevitsa Village, Ponor Mountain, Svoge Municipality, Bulgaria. - Year of Discovery: 1963. - Official Depth: 561 meters. - Official Length: 25 354 meters. It is highly significant to note that this massive length of over 25 km was officially confirmed and mapped during extensive caving expeditions. Because the cave network is incredibly complex and branches out into unexplored sectors, active research, mapping, and diving expeditions by speleological clubs continue to this day. Consequently, these record-breaking parameters are expected to grow even further as new underground galleries are unlocked. Essential Accessibility and Safety Info: Due to its extreme depth, vertical drops, tight passages, active underground rivers, and highly technical structures, Kolkinata Dupka is not developed for regular commercial tourism. Access to the cave system is strictly limited to certified speleologists and expert cavers trained in advanced single-rope techniques (SRT) and alpine rescue. For general travelers and outdoor enthusiasts, the surrounding Ponor Mountain and Zimevitsa village area offer excellent conditions for panoramic trekking, crisp mountain air, and landscape photography among striking surface karst landforms.
Sofia Province
3.3 km away
Sofia Province
3.3 km away
Sofia Province
4.4 km away
Kolkina dupka is located in Sofia Province, Bulgaria.
Kolkina dupka is most easily reached by car. Use the coordinates above to navigate, or open the location in OpenStreetMap or your preferred maps app for turn-by-turn directions. Public transport options vary by region — for remote destinations a rental car gives the most flexibility.
Caves can be visited year-round — the temperature inside stays roughly 10–12°C regardless of season. Spring and autumn are quieter than peak summer. Bring a warm layer and sturdy footwear; some caves close in winter when access roads become impassable.
Access to caves varies. Show caves typically run guided tours during posted opening hours; wild caves require proper equipment and experience. Inside, the temperature stays cool year-round (~10–12°C) — bring a warm layer, sturdy non-slip footwear, and a torch even on guided tours.
