Mysterious painted skulls in Moravia.

The world's greatest slide descends 18 stories from this looping mountaintop viewing platform.

Hundreds of boat-shaped headstones fill this graveyard as part of a centuries-old custom with mysterious origins.

A self-proclaimed libertarian micro-state on a tiny bit of disputed territory between Serbia and Croatia.

Built as an anti-fascist tribute, this surreal Yugoslav memorial became an unwelcome symbol after the Croatian war for independence.

Massive, unfinished broadcasting station stands as a monument to the fall of communism.

This massive concrete sculpture is said to be the heaviest communist monument on Earth.

Said to be the only museum in the world dedicated to the most classic of all blooms, the rose.

An abandoned saucer-shaped monument in the Bulgarian mountains.

A mountain pass in Bulgaria's Balkan Mountains was the site of four historic battles.

This massive underground salt mine now holds a sci-fi theme park in its depths.

Street artists transformed an abandoned air vent into the beloved Star Wars robot.