This iconic 1,000-year-old medieval castle is a favorite of the film industry, most notably as the location for Hogwarts in Harry Potter.

Britain's only herd of free-ranging reindeer.

A glacial pothole was once a hideout for a notorious Scottish outlaw.

A site of pagan worship which still attracts people looking for fairies.

This bronze statue was erected to honor a small Scottish town's beloved stray cat.

The burial site of a murdered bishop and his alleged killers.

Once a state-of-the-art tuberculosis treatment spa, these ruins are now ruled by paintball players.

The now-overgrown beach resort was once frequented by Yugoslav military elite.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'

Gargoyle head that brings good luck.

A full figure 4th century incorruptible saint lies in a glass coffin in Croatia.

Croatia's towering concrete blossom grows from the site of a World War II concentration camp.

There's a mini version of Iguazu Falls hidden in the Balkans, and it's got a rope swing.

When Croatia became independent of Yugoslavia, the splintering governments left behind these concrete tunnels.

An ethereal glowing blue ocean cave in Croatia.

Formerly Yugoslavia's "forbidden island," this sleepy little city still holds the abandoned remains of military strongholds.

A wonderfully strange collection of 500+ stuffed frogs doing people things.

Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

This cluster of little wooden huts once ground local farmers’ wheat into flour during the days of the Austro-Hungarian Empire.

A musical instrument played by the sea.

This Croatian fairytale castle is slowly falling apart thanks to years of neglect.

A miniature train-ride through Slovenia's largest cave system.

Where the lovelorn find a home for their sentimental keepsakes.

This huge metal monument is slowly being stripped to its concrete skeleton.