Imagine a place where reality turns into a fairy tale. Where the underground silence is broken only by the dripping of water, and a world that looks as if it was carved from fantasy unfolds before your eyes. Welcome to Postojna Cave, an underground palace where nature has created its most precious treasures and where legends of dragons come to life.

 

How it began?

In April 1818, Postojna Cave (Postojnska jama) was preparing for the ceremonial visit of Emperor Francis I and Empress Caroline Augusta. At that time, only a small part of the cave—a few hundred meters from the entrance—had been explored. Yet, whispers of its beauty had already spread far beyond the local borders.

To make the imperial couple’s visit truly grand, the local residents decided to build a welcome pyramid with a festive plaque on a rock above the underground river. However, while hanging it, something happened that changed history—a previously unknown part of the cave was discovered.

The brave lamplighter Luka Čeč, who was tasked with placing the plaque, crossed the river on an improvised bridge and climbed onto the rock. But instead of turning back, he disappeared into the darkness. When he emerged after long minutes, he shouted words that would go down in history: "This is a new world, it is paradise!"

Čeč became the first person to set foot in the previously unknown parts of Postojna Cave. Using broken-off stalactites, he marked his way back—an improvised compass that saved his life. His discovery paved the way for what we now know as the longest publicly accessible cave in Europe.

 

What awaits you?

Your adventure begins right at the entrance, where you will embark on an unforgettable ride on an electric train, which will take you directly into the heart of the cave—the journey itself through the dark passageways is an experience you won't soon forget.

Upon arrival, an approximately 1.5-kilometer-long guided walking tour awaits, during which you will discover underground wonders that seem as if they don't even belong to this world. Gigantic stalagmites, remarkable limestone formations, and crystal-clear underground rivers create a magical, breathtaking atmosphere.

One of the highlights of the visit is the Concert Hall —a massive chamber with such exceptional acoustics that real music concerts are occasionally held here. It is right here that you will fully realize how wonderfully nature can combine beauty with majesty.

Address: Jamska cesta 30, Postojna

 

Mysterious Little Dragons from the Depths

Pale, blind, with red gills and serpent-like bodies—creatures that have evoked curiosity and fear for centuries. Locals considered them the offspring of a cave dragon, which, according to legend, inhabits the dark depths of Postojna Cave. Today, we know them as the olm—a unique creature that lives only in a few underground rivers of the Dinaric Karst.

These mysterious salamanders have superpowers that any comic book hero would envy. Although they have no eyes, they see through their skin. They breathe with both gills and lungs. They can survive without food for up to 12 years. And they live for over 100 years.

For a long time, scientists tried in vain to discover how they reproduce. Then, in 2016, a small miracle happened—21 babies hatched in an aquarium right inside Postojna Cave, instantly becoming a sensation.

Today, you can see the "little dragons" during a cave tour—and believe us, their strange charm will leave a deep impression on you.

 

The slow world of giants

When Postojna Cave was discovered, people began to dream—of cave trains, electric lighting (which was installed here even before it reached Ljubljana), and adventures straight out of Jules Verne's novels. But even the wildest human imagination cannot compete with what nature itself has created here.

More than 50 meters below the surface, giant underground chambers open up, along with narrow passages, rock "mountains," and massive stalactites. The largest of them— a stalagmite called Nebotičnik (Skyscraper)—measures an impressive 16 meters and, up close, looks more like a wall than a stalactite. It is approximately 150,000 years old. And yet, within the cave, it is a "youngster," as the oldest parts of this underground world formed three million years ago.

But Skyscraper is not the only giant. Nearby stand other majestic formations—a stalagmite forest called the Giants. Above this world of stalactites stretches a collapsed chamber called Calvary, formed by the collapse of the ceiling. It is so vast that London's Saint Paul's Cathedral could fit inside it—not just once, but twice. Today, the ceiling is stable, allowing visitors to safely climb to the top and admire this "cave mountain," which resembles a frozen stone avalanche.

During the tour, you realize how slowly everything happens here. Stalactites grow at a rate of roughly one millimetre every ten years. Some have been growing for thousands of years, just by millimetres. And they create scenes that take your breath away.

 

The only cave post office

If you take selfies today, in 1900 you would have been writing postcards in Slovenia. And right from underground! That's because Postojna Cave operates the world's only cave post office.

The small stone post office, hidden half a kilometre underground, served exclusively the cave's visitors. It was a sensation—in just three hours on Whit Monday in 1904, they sold almost 14,000 postcards here.

Even today, you can buy a special postcard in the Concert Hall, affix it with a cave stamp, and send a piece of underground magic out into the world. It's a romantic greeting from a time when "I was here" meant more than an instant like.

 

Our useful tips and recommendations:

When to go: You can visit Postojna Cave all year round—a stable temperature of around 10 °C (50 °F) inside makes it a great refuge from the summer heat and a pleasant trip outside the main season. It is busiest during July and August, so if you have the chance, we recommend planning your visit for May, June, or September when the cave is quieter.

What to bring: Even on a hot summer day, it's chilly inside, so don't forget to pack long pants and a sweater or jacket. Comfortable shoes with good grip are also important, as the path can be damp and slippery in places.

Tickets: We recommend purchasing them online in advance, especially during the high season. This allows you to avoid the queues, and you can also choose a combined ticket for Predjama Castle, which is located just a few minutes' drive from the cave and literally grows out of the rock.

Parking: A large parking lot, Postojna Cave Parking, is located right at the complex where you can park conveniently. The parking lot is paid, but it is well-organized and just a few minutes' walk from the entrance to the complex.

Address: Veliki Otok 1, Postojna

 

Predjama Castle

For over 800 years, perched on a 123-meter-high cliff as if born from the rock and legends themselves, stands the world's largest cave castle — Predjama Castle.

Behind its walls lie secret tunnels used by the famous robber knight Erazem for his expeditions. And directly beneath the castle lives a colony of bats—nature and history quite literally merge here.

This Guinness World Record holder and a regular on lists of the "world's most stunning castles" will charm you not only with its location but also with its romantic spirit.

Address: Predjama 1

 

Our final tip:

Want to make the most of your visit? Arrive early in the morning—you’ll avoid the crowds and have plenty of time to explore also Predjama Castle at a relaxed pace.