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

The fairy tale castle of the "fairy-tale king."

This famous archeological mystery may be an ancient example of movable type.

This 15th-century island fortress later served as home to the executioners no one wanted to live near.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

This legendary city has been a tourist attraction for centuries.

Monasteries on rock pillars, once accessible only by frayed ropes.

Two stone columns flank the grand Venice square, but there were supposed to be three.

Go inside to really appreciate this 500-year-old technological masterpiece.

A whimsical bridge adorned with decorative dragons.

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

Martin Bricelj Baraga's monolithic sculpture measures the blueness of the sky, and changes color to match it.

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

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

This one-time health resort was used by aristocrats around the world.

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

The world's oldest grape-producing vine has survived four centuries of turmoil and even has its own anthem.