Meet Predjama, the world's largest castle built in a cave

(CNN) -- Predjama is one of the world's most spectacular castles, built at the mouth of a cave complex at the end of a valley in southwestern Slovenia.

Situated halfway up a 123-meter vertical cliff, it has been on record since 1202 and is listed by Guinness World Records as the world's largest cave castle.

With a Renaissance façade dating back to the 1580s, the word "majestic" falls short to describe it. However, for tour guide and historian Vojko Jurca, one of the highlights is, at first glance, a bit disappointing.

"This is it," he says proudly, indicating an outhouse with a sloped roof and a boarded-up door.

It may seem unremarkable, but the story behind it isn't.

The story centers on the robber baron Erasmus von Lueg, a local "Robin Hood" hero who fled to the castle in the mid-1480s after killing Count Pappenheim, marshal of the Habsburg imperial court , in a duel whose legitimacy was discussed.

In retaliation, the German Emperor Frederick III ordered the siege of Predjama.

But Erasmus held his ground, aided by a network of secret tunnels carved into the rocks that allowed him to bring provisions and collect rainwater.

He taunted his adversaries by sending them fresh cherries brought from the Vipava Valley, 20 kilometers to the west, using those underground passages.

The end would come, after a year and a day, when Erasmus was betrayed by a servant.

According to Jurca, when Erasmo went to the latrine located on a terrace on the third floor, the servant lit a wooden torch as a signal. Moments later, a cannonball whistled through the air, killing Erasmus in the midst of his last evacuation.

The latrine was clearly rebuilt in the intervening years.

Slovenia to Westeros

Finishing moves: Erasmus was killed when a cannonball hit the castle latrine. (Credit: John Malathronas)

The manner of Erasmus' death has not escaped the attention of "Game of Thrones" fans, who point to the similarly undignified end of Lord Tywin Lannister, who was shot from a crossbow while on the throne of His bathroom.

They also point out that the last owners of Predjama, the Windisch-Grätz family, who used the castle as a hunting lodge until the end of World War II, have a wolf on their coat of arms, the seal of the noble house of the Stark.

Coincidentally, the writer George R. R. Martin visited the castle one afternoon in June 2011, after a book signing in Trieste.

"On the way home, we stopped at the most amazing castle, built in the mouth of a huge cave. Definitely have to model a Westeros castle after this, it was a sight to behold, especially at night ", he says in a blog post.

Legend and history are only part of the appeal of Predjama Castle. You have to visit it to understand how human initiative was so organically linked to nature.

When approaching the castle from any direction, it is almost completely hidden, only visible at the last moment, while the surrounding sentinels would have been able to spot anyone approaching immediately.

Once inside, it's clear that safety, rather than comfort, was the main concern in the Middle Ages: the castle is impenetrable, but the cold and damp make it almost uninhabitable.

Today, entrance to the castle involves going over a drawbridge. The original entrance was further up, where two dim doors are glimpsed. They were accessed by stairs that quickly withdrew.

In ancient times, visitors entered the courtroom first, where harsh justice was meted out. Few of the ruler's subjects were allowed to go further, unless they were unlucky.

Behind a thick wooden door is a torture room, uniquely located in a real dungeon. The preferred punishments here were the rack, on which prisoners were stretched out, and the horse, a painfully pointed triangular contraption on which prisoners were made to ride.

Next, one of the most pleasant spaces. The dining room is insulated by nearly five-foot-thick walls, and warmed by the small but functional kitchen, in which a crack functions as a natural extractor hood.

You can also inspect an original latrine, a seat that juts out of the cliff and allows gravity to do the dirty work. Erasmus would have used straw, dried moss, and cabbage leaves instead of toilet paper, or at least he would have done so before getting blown to pieces.

"Murder Holes"

The castle barracks is now a weapons museum. (Credit: John Malathronas)

Ascending more stairs to the third story reveals cannon handles, arrow slits, and murder holes or machicolations that were used to pour boiling oil or molten resin on besiegers.

There is the open terrace. From this point there is a view of the entire valley, as well as the most famous latrine in the history of Slovenia.

Next is the bedroom. It is the warmest room, since it is the only one with a fireplace. The castle keepers lived here until the 1980s.

Upstairs there is an attic that served as a barracks and a lookout. The views of the Lokva valley are uninterrupted and gorgeous.

The barracks has been converted into a weapons museum displaying medieval weapons such as axes, halberds, crossbows, and flails.

Interestingly, a hallway in this place leads directly to the torture room. Presumably anyone sleeping during the service could be casually dragged into it.

From here you can also enter the bowels of the cave, exploring until the light at the entrance is reduced to a point, allowing you to contemplate the surroundings.

The extensive limestone cave system in southern Slovenia is called karst, from the Latin name for Carsus for the plateau above Trieste.

Being the best-known limestone for centuries, the word has become generic, describing any limestone with cavities like Swiss cheese with holes in it.

Below the castle, a large cave stretches for 14 kilometers, the second in length after the nearby complex of Postojna.

There is no tourist infrastructure in this great cavern, but it is possible to visit it during the summer months with the appropriate caving equipment, lamps, and a specialized guide. It is closed in winter because a colony of Schreiber's long-fingered bats uses it to mate and hibernate.

Memorial tree

The castle's Renaissance façade dates from the 1580s. (Credit: Jure Makovec/AFP via Getty Images)

Back in the castle, a one-way system leads to the knights' room, notable for its Gothic niches and a ceiling painted with ox's blood.

Here and there you can see how the builders of the structure made efficient use of its rocky situation. A small well near the exit became a kennel for hunting dogs, while the mouth of a cave under the castle served as a stable.

Leaving the castle, guide Vojko has one more stop on his tour: a nearby village where a diseased lime tree is propped up in the Nuestra Señora de los Dolores cemetery.

The church was consecrated around 1450 by the Bishop of Trieste, future Pope Pius II.

"Legend has it that this lime tree was planted on the grave of Erasmus," says Vojko.

The tree was badly damaged by a fire in 2001, but it meant so much to the townspeople that tree surgeons were called in and its trunk was split and repaired.

It still stands proudly, like Predjama Castle itself.

To learn more, visit: postojnska-jama.eu/en/predjama-castle

John Malathronas is a travel writer and photographer. Follow him on @malathronas