Artwork tucked within the trees greets visitors with surreal sonic experiences.

Walk or bike along a narrow strip of Belgium sandwiched by German territory.

It took 40 years to build this Eden-like garden in Marrakech, later restored by Yves Saint-Laurent.

An Albanian monument to the Communism that nearly crushed the country is now a crumbling wreck.

This Italian foot path winds through the mountains via 52 individual tunnels.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

Hundreds of thousands of concrete bunkers crowd Albania long after the fall of Communism.

A medieval bridge stretches over a sulfur-rich river that leads to year-round natural hot springs.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

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

This fairy tale forest hides scenes from some of the more obscure and bizarre Western nursery stories.

Hiding the longest subterranean river known in the world.

Descend into the tunnels to experience the life of a coal miner.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

This narrow Ghent alleyway is an officially sanctioned street art tunnel.

What was once a bustling mining installation is now a bustling hub of contemporary art.

This ghost town in Belgium will lose its street art when it ceases to exist.

The world's tallest boat lift stands as a massive piece of industrial tourism.

Six turbines towering over a wide road for passersby.

Rare wooden escalators lead deep down into an otherwise staggeringly monotonous tiled tunnel.

Most prolific publishing house in the 1600s open to the public.

Theme park featuring miniature replicas of European monuments.