In the heart of Slovenia, hidden between the Alps and the Adriatic Sea, Predjama Castle and the Postojna Caves offer a fascinating experience for intrepid travellers. Perched atop a cliff of 123 metres, the castle stands out not only for its daring medieval architecture but also for the legend of Erazem of Predjama, a rebellious knight who took refuge here during a siege thanks to an intricate system of secret tunnels. Just a short distance away, the Postojna Caves unfold as a 24-kilometre underground labyrinth, accessible by a 19th-century train that allows visitors to admire stunning stalactites, stalagmites and passageways sculpted over millions of years.
History and context: Predjama, the medieval hideaway and Postojna, the underground cathedral
Perched on a staggering cliff 123 metres high, Predjama Castle is an extraordinary example of the fusion between medieval architecture and natural geology. Built in the 13th century its strategic location made it almost impregnable, taking advantage of the protection offered by the surrounding rock. This fortified refuge, designed to withstand both the forces of nature and enemy attacks, features an intricate system of secret tunnels connecting it to the outside—a key feature that sets it apart from any other medieval fortress.
The castle is inextricably linked to the figure of Erazem of Predjama, a rebellious knight from the 15th century who defied the Habsburg Empire. According to legend, Erazem took refuge in the castle during a siege lasting over a year using the tunnels to obtain provisions and brazenly taunt his enemies. Known for his daring defiance and reputed generosity to the poor, Erazem earned the nickname “Slovenian Robin Hood”. However, his story ended in a tragic and somewhat ironic way; betrayed by a servant, a cannonball hit him while he was using the bathroom, bringing his legend to an end.
Today, the castle not only preserves its medieval feel, but also offers a glimpse into the past through its exhibitions. Visitors can wander through its Gothic chambers, uncover the enigmatic tunnels leading to the cave below and delve into Erazem’s intriguing story through historical reenactments and interactive displays.
Just a few kilometres from the castle, the Postojna Caves offer a spectacular contrast, showing nature’s creative power. These caves, with over 24 kilometres of passageways, chambers and galleries, are the result of millions of years of erosion caused by the River Pivka. Although they have been known since ancient times, the Postojna Caves began welcoming visitors in the 19th century, becoming one of the first caves worldwide to feature electric lighting. In 1872, an underground train was inaugurated which still carries visitors through the rock formations like the spectacular stalagmite known as “Brilliant”.
Together, Predjama Castle and the Postojna Caves make a perfect pair where human resilience and nature’s artistry combine in an unforgettable experience. Both places tell tales of ingenuity, defiance and discovery that have fascinated generations of visitors, establishing themselves as two of Slovenia’s greatest treasures.
How to get there: the route to an underground world of wonders
Getting to Predjama Castle and the Postojna Caves from Ljubljana, the capital of Slovenia, is an easy journey that takes you through green landscapes and gentle mountains. Ljubljana is less than an hour from Postojna via the A1/E61 motorway, making it perfect for a day trip. The castle is just nine kilometres away from Postojna, which is accessible by car or a shuttle service.
Travellers who prefer public transport can also take buses from Ljubljana’s main station to Postojna. Although the journey is a bit slower, the scenery more than makes up for it. During high season, organised tours are offered that include transport, tickets and guides, ideal for those who want to explore without any logistical worries.
What to see at Predjama Castle: following in the footsteps of Erazem, the Slovenian “Robin Hood”
Predjama Castle not only impresses with its location on a cliff 123 metres high but also with the stories and secrets it holds within its walls. As you cross its drawbridge, you step into a world that blends medieval aesthetics with an atmosphere full of mystery. Each room unveils a fragment of its history, from grand chambers decorated with period-style furniture to the medieval kitchen showcasing ancient tools that illustrate daily life in the castle.
One of the biggest attractions is the underground tunnels accessible during the summer season. These elaborate tunnels, carved directly into the rock, link the castle to the outside world, enabling secret resupply during sieges. It is an elaborate maze with four floors, making it the second-longest cave in Slovenia. The Gothic chapel, still well preserved, is another highlight with its austere architecture and religious symbolism.
From the balconies and defensive towers, the castle offers stunning panoramic views of the valley and the forests surrounding it, which are especially magical at dawn or dusk. Information boards and interactive guides help visitors relive the legendary exploits of Erazem of Predjama, the rebellious knight whose tale of wit and tragedy adds to the romance of the place.
Plus, inside the museum you can discover weapons, armour and documents that retrace the region’s historical context, providing an immersive experience in one of the most unique castles in Europe.
Tips for your visit: how to make the most of your experience
A visit to Predjama Castle and the Postojna Caves requires a bit of planning but the rewards are enormous. Combined tickets, which cost €41.90, let you comfortably explore both places and are usually well timed so you won’t be rushed. You can also buy a ticket for €51.90 which includes a visit to the vivarium, home to over 150 species of cave-dwelling animals like the incredible olm, known for centuries as the “baby dragon”. It also includes the Karst Cave Expo, which interactively explains the creation of underground karst phenomena and the cave’s history.
It’s a good idea to arrive early in the morning to avoid the crowds, especially during the summer months. With a constant temperature of 10 °C year-round in the caves, a light jacket is essential, even in the height of summer. Comfortable footwear is equally essential as both the caves and the castle involve walking on uneven ground.
For a deeper dive, consider hiring a local guide who shares historical insights along with captivating tales of Slovenian mythology and culture.
Visits in the surrounding area: the Škocjan Caves and the horses at Lipica Park
The Karst region, where Predjama Castle and the Postojna Caves are located, is full of attractions that are well worth exploring further. A mere half-hour drive away, the Škocjan Caves provide a striking contrast to Postojna, featuring a colossal underground canyon resembling a frozen river. Declared a UNESCO World Heritage Site, these caves are a spectacle of titanic proportions.
Lipica Park, home to the graceful Lipizzaner horses, renowned globally for their beauty and ties to European equestrian heritage, is another must see. The region also boasts picturesque villages like Vipava where travellers can enjoy local wines and traditional cuisine.
