A kaleidoscopic warehouse-maze of handmade neon signs.

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

This massive subterranean fissure is known as the "underground Grand Canyon."

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

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

A whimsical bridge adorned with decorative dragons.

A trough of 700 strange bronze faces runs through a narrow alley in Ljubljana's old town.

An abandoned tuberculosis hospital said to be haunted by the patients who died within its walls.

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.

This giant sculpture made of trash is a critique of society's wastefulness.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

What started as a tongue-in-cheek shrine is now a full-blown museum celebrating "The Hoff" and his longtime love affair with Berlin.

An unusual and beautiful form of mass transit serves the city's steepest neighborhoods.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

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

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

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

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

Rippling sand dunes frozen in the Arizona rock.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

The highest bridge in America was built for an almost unnervingly small amount of money.

When ecosystems collide in the arid Southwest.