No need to strap in for a "ride" on this walkable roller coaster.

This "floating railway" is one of the world's oldest monorail systems.

According to a satirical conspiracy theory that persists today, this German city of 300,000 is a hoax invented by the CIA.

Handsomely crafted representations of our round planet.

The idyllic island where the philosopher Jean-Jacques Rousseau spent “the happiest time of his life.”

Along the banks of the River Rhine lies a park that seems unassuming, but beneath the surface lies a long and fascinating history.

The last bastion of Roman presence north of the Alps looms over a German town.

The birthplace of Karl Marx is now a museum dedicated to the communist revolutionary's life and work.

Dedicated to the American general whose reply to a German demand for surrender was simply "Nuts!"

An early 20th-century sanatorium, long abandoned and now being reclaimed by nature.

This abandoned Belgian fortress is purposefully being left to nature.

This sprawling Belgian fort was once thought of as impenetrable but now it is simply an abandoned relic.

An image of the legendary saint stands in the shadow of a cathedral she liberated.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

This cemetery features modernist statues as strange as its name.

Hidden well off the beaten path in Catalonia is this crumbling medieval castle that is slowly being covered in graffiti.

Single runway interrupted by a busy road that cuts across its middle.

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

This ironic war memorial thumbs its nose at a campaign of inedible humanitarian aid food products.

A number of craters left by fatal mortar strikes have been filled with red resin to remember those lost during the Siege of Sarajevo.

Oriental bazaar in the heart of Sarajevo.