Rare karst landscape eroded from a flat seabed.

This quaint Spanish village agreed to be painted blue as a marketing stunt but found that they preferred it that way.

A charming Spanish village sits atop this natural limestone overpass.

A science fiction-inspired apartment building designed by a famous Spanish architect.

A once-secret library of Freemason history in Catalonia.

This massive fiberglass Gulliver turns every visitor into a Lilliputian.

A completely underwater art museum sends a stark message about humans' impact on the environment.

The world's largest wooden structure.

The final resting place of the great navigator, or maybe his brother.

This cafe offers a curated collection of treats and tipples made by monks and nuns.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

A Spanish town built into the cliffs.

This house's itty bitty size means no humans allowed.

Giant eggs, walls of bread, and nightmare surreality mark the largest collection of works by Salvador Dalí.

An architect transformed this abandoned cement factory into his castle-like workshop.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

An ancient Egyptian temple in the middle of Madrid, Spain.

An unusual stroll through gentlemen's erotica demonstrates that pornography is timeless.

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

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

This semi-secret storybook hedge maze is also the oldest garden in the city.

Three bridges and one giant canyon make up this fantastic Spanish settlement.