At the Predjama Castle, built within a cave mouth in south-central Slovenia

 After the fall of the Roman Empire, Lombards settled in Carniola, followed by Slavs around the sixth century CE. As a part of the Holy Roman Empire, the area was successively ruled by Bavarian, Frankish and local nobility, and eventually by the Austrian Habsburgs almost continuously from 1335 to 1918,

====================================================================
(in the historic region of Slovenia's Inner Carniola.) At Predjama Castle (Slovene:[Predjamski grad or grad Predjama], a castle built within a cave mouth in south- central Slovenia, This castle (shown here) is located in the village of Predjama) Just nine kilometers (~6 mi.) from Postojna Cave, the Renaissance-style Predjama Castle, is one of Slovenia’s most popular attractions. The castle is now a museum featuring an eerie dungeon, many 16th-century treasures, and a secret hiding spot called Erazem’s Nook, after Erazem Lueger -- Slovenia’s "Robin Hood," -- who hid out from the authorities here. Predjama is also one of Europe's most dramatic castles. (It teaches a clear lesson: if you want to build an impregnable fortification, put it in the gaping mouth of a cavern halfway up a steep cliff.) Its four storeys were built piecemeal over the years from 1202, but most of what you see today is from the 16th century. (It looks to be quite unconquerable.)

+ An audioguide (available in 15 languages) details the site's highlights and history. The castle has great features for kids of any age – holes in the ceiling of the entrance tower for pouring boiling oil on intruders, a very dank dungeon, a 16th-century chest full of treasure (unearthed in the cellar in 1991), and an eerie hiding place at the top called Erazem's Nook, named for Erazem (Erasmus) Lueger.

+ Lueger was a 15th-century robber-baron who, like Robin Hood, stole from the rich to give to the poor. During the wars between the Hungarians and the Austrians, Erazem supported the former. He holed up in Predjama Castle and continued his daring deeds with the help of a secret passage that led out from behind the rock wall. In 1484 the Austrian army besieged the castle, but it did prove impregnable. Erazem mocked his attackers, even showering them with fresh cherries to prove his comfortable situation. But the Austrians had the last laugh -- finally hitting him with a cannonball as he sat on the toilet. (An ignoble fate for a dashing character.)

+,The cave below the castle is part of the Predjama cave system. It is open to visitors from May to September (but closed in winter so as not to disturb its colony of bats during their hibernation). Another adventure option is to visit the narrow Erazem's Passage, through which the besieged knight was connected with the outside world. (Joint tickets can be bought for the castle and Postojna Cave.)

+ In July and August, a handy shuttle-bus service runs between the cave and the castle; it is free for guests who buy a combined ticket for both attractions.