Introduction
Planina Cave (Planinska jama) and the Rakov Škocjan valley together create one of the most impressive karst systems in Slovenia. Here the landscape switches between worlds: subterranean rivers flowing through the dark, then open dolines, stone arches, emerald pools, wetlands and quiet forest meadows on the surface.
This is where you feel the power of Slovenia’s underground: rivers disappear into cave systems, travel under hills and reappear in a collapsed valley carved out of former cave ceilings. For nature lovers, geologists and photographers, Planina Cave and Rakov Škocjan are among the most fascinating places in the Lakes & Valleys region.
Geography and Geological Origin
The whole area is shaped by the karst hydrology of the Javorniki–Snežnik massif, where slightly acidic water slowly dissolves limestone and opens tunnels, shafts and large caverns.
Planina Cave formation
Planina Cave is one of Europe’s largest water caves and the meeting point of two underground rivers:
- Pivka River – flowing through the famous Postojna Cave system
- Rak River – flowing from the collapsed valley of Rakov Škocjan
They join inside Planina Cave, creating the longest underground confluence in Slovenia. The explored passages stretch for more than 6 km, with huge chambers, active river galleries and frequent seasonal flooding.
Rakov Škocjan formation
Rakov Škocjan is an open-air karst valley created when a giant underground cave system collapsed thousands of years ago. Visitors now walk through what was once the interior of a massive cave hall. The valley features:
- giant dolines (sinkholes)
- natural stone bridges
- strong karst springs
- remains of partly collapsed cave ceilings
Together, Planina Cave and Rakov Škocjan form parts of the same hidden hydrological network.
What to See: Key Natural Features
1. Planina Cave entrance and underground river Must-see
The wide cave entrance with a powerful emerald river flowing out is one of the most striking karst scenes in Slovenia. Even without going deeper inside, the view from the mouth of the cave is worth the trip.
2. Natural bridges of Rakov Škocjan
Two huge stone arches mark where cave ceilings stayed intact while the rest of the system collapsed:
- Veliki naravni most (Great Natural Bridge)
- Mali naravni most (Small Natural Bridge)
These bridges span the collapsed valley and are among the most photographed natural formations in the region.
3. Rak River channel
A shallow, clear karst river runs along the valley floor, cutting through gravel, mossy stones and small pools. In low water it reveals more rock detail and side channels.
4. Wet meadows and karst springs
Seasonal water channels, marshy patches and lush vegetation thrive in the lowest parts of Rakov Škocjan. In spring these areas are especially green and full of life.
5. Forested karst plateaus
Beech and oak forests surround the valley, giving shade in summer and golden colours in autumn. Short side paths lead from the main track up to viewpoints above the bridges and dolines.
6. Cave fauna
Planina Cave hosts several bat colonies and specialised cave invertebrates adapted to complete darkness. Deeper, inaccessible sections also belong to the habitat of the olm (Proteus anguinus).
Best Time to Visit
Spring
High water levels, bright green vegetation and dynamic river scenes. Some low-lying paths can be muddy but the valley feels very alive.
Summer
Stable access, steady water flow and long daylight. Ideal for combining the cave entrance with a full walk through Rakov Škocjan.
Autumn
Golden forests, softer light and calm water levels. Natural bridges and dolines look especially good in side light.
Winter
Lower water levels reveal extra rock features and channels. Cave entrances can be filled with mist and ice, which creates an atmospheric but colder setting.
Photography Highlights
- Long-exposure shots at the Planina Cave river entrance
- Great and Small Natural Bridges photographed from above and from the valley floor
- Mirror reflections in quiet sections of the Rak River
- Misty mornings when fog hangs between the trees and stone arches
- Close-up textures of limestone walls and collapsed cave fragments
The best light comes early in the morning or late in the afternoon when shadows are long and the stone structures gain depth and contrast.
How to Get There
Planina Cave
- By car: about 40 minutes from Ljubljana and 10 minutes from Postojna
- Parking: small parking area near the cave entrance
- Tours: guided boat tours are possible when water levels allow; they are seasonal and must be booked or checked in advance
- Access: the entrance is easy to reach on foot, while the interior is accessible only with guides
Rakov Škocjan
- By car: around 10–15 minutes from Planina; parking near Malo polje or Veliki naravni most
- Trails: easy to moderate walking routes link the natural bridges, river sections and viewpoints
- Cycling: gravel roads around the valley allow for relaxed bike exploration
Trail difficulty
Overall routes are mostly easy, but some rocky and rooty sections near bridges and cave entrances need stable footwear and attention, especially after rain.
Interesting Facts
- Planina Cave contains the largest underground confluence in Europe, where the Pivka and Rak rivers meet.
- Rakov Škocjan is a collapsed cave system, meaning that visitors walk along the floor of what used to be a large underground chamber.
- The system is part of the wider hydrological network linked to the Postojna Cave and other classic karst sites.
- The natural stone bridges are surviving pieces of former cave ceilings that stayed intact thanks to thicker, stronger rock layers.
- Rare cave fauna, including the olm, live in deeper, flooded passages that are not open to the public.
Conclusion
Planina Cave and Rakov Škocjan form one of Slovenia’s most remarkable karst landscapes – a place where underground rivers shape valleys, carve natural bridges and leave behind collapsed cave rooms now open to the sky.
The mix of cave entrances, emerald rivers, stone arches and quiet forested meadows makes this area a must-see for anyone interested in geology, wild landscapes or atmospheric nature photography. It is a compact, accessible window into the hidden depths of the Lakes & Valleys region.
