Built halfway up a 400-foot vertical cliff face, Predjama Castle is the world's largest cave fortress — and is said to have once housed the Slovenian Robin Hood.

 Built halfway up a 400-foot vertical cliff face, Predjama Castle is the world's largest cave fortress — and is said to have once housed the Slovenian Robin Hood. 

As the story goes, a noted robber-baron named Erasmus von Lueg fled to the castle in 1484 after killing a high-ranking Marshal in the Hapsburg Court. In retaliation, the Austrian Emperor sent his army after von Lueg, who evaded capture for months by using a complicated network of tunnels built under the castle. He even teased the Austrians by sending them cherries he'd picked in a valley he accessed through the tunnels, some 13 miles away from the palace. But almost exactly a year after his game of cat and mouse began, von Lueg was betrayed by a servant — and killed by cannonball while using the castle's latrine.