Made up of an underground network of caverns and rivers so vast it takes one and a half hours to explore, spectacular Postojna Cave Park is one of the most dramatic in the world. The cheerful little train tour is magical, but older kids and teens might prefer the on-foot explorer experience.
Either way, make sure eyes are peeled at all times for glimpses of Vivarium Proteus. These bashful lizards, affectionately known as Baby Dragons, are Postojna natives and spotting them never gets old.
Don’t forget to leave some time for the up-top marvel of nearby Predjama Castle: built into a cliff face, it’s almost as awe-inspiring as the caves below – but not quite.