The Predjama Castle in Slovenia is the most unique one I have come across. Nesting comfortably in a niche on the vertical face of a steep cliff, this medieval structure stood the test of time and survived many sieges through the centuries.
Exploring this castle from within, I was fascinated by the way every aspect of the natural cave system was harmoniously blended into the man-made structure to make this fortress habitable. These caves shaped a portion of the internal castle walls. Its natural shafts provided ventilation, a drainage system, water supply and even a secret passageway through which goods could be transported during times of war.
To me, this formidable structure symbolizes r...