A 19th-century subterranean reservoir repurposed as a contemporary art cave.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

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

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

This former estate of a fascist leader is now a burnt out ruin leading to a system of secret tunnels.

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

One of the world's oldest olive trees, thought to be over 2,000 years old.

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

This abandoned Olympic skiing facility still bears the scars of the Siege of Sarajevo.

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

Serbia's master of striking memorials erected a forgotten, hidden gem in the hills outside a tiny village.

This abandoned Slovenian military barracks has become a punky-political art squat.

A whimsical bridge adorned with decorative dragons.

The "dragon babies" of southeastern Europe.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

A bridge destroyed three times: once as a ruse, then in an actual attack, and finally for the movies.

An ethereal glowing blue ocean cave in Croatia.

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

An old slaughterhouse now holds the largest collection of pig artifacts.

Remnants of a cone-shaped Nazi bomb shelter.

Power line with pylons on huge concrete bases to prevent terrorist attacks.

The tallest outdoor elevator in Europe rockets passengers on a dizzyingly precarious ride to the top of a mountain.

Museum featuring strange and enchanting toys of the past.

The bizarre visions of H.R. Giger, tucked away in a Swiss medieval city.