This "flat geyser" bubbles up out of the ground periodically like a disappearing river.

This religious complex carved into a cliff is steeped in legends of miraculous stags and the Holy Grail.

A display of torture devices used in the Spanish Inquisition and other scourges of medieval Europe.

Blue-green pools and smooth stones comprise one of Spain’s most idyllic hidden wonders.

A medieval village holds a very modern hotel.

This century-old ruined temple was reborn as "The Church of Skate."

Giant granite sculptures representing family on the northern coast of Spain.

Volcanic rocks ground down into sand make this Spanish beach as black as night.

"Alleys of Stone" form natural mazes in Spanish natural park.

Devastated landscape used for hundreds of years by the Romans as their primary mining site.

Mine shafts and hard pastries await visitors at this massive mountain of salt.

A once grand hotel now sits eerily abandoned in the Catalan countryside outside Barcelona.

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.

A Romanesque tower appears when water levels drop.

This magical space partly designed by Antoni Gaudi is one of the best examples of romantic gardening in the Mediterranean.

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

Numerous sculptures set along hiking trails symbolize and idealize the relationship between man and nature.

A charming Spanish village sits atop this natural limestone overpass.

Of course Salvador Dalí lived in a castle...

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.

Stunning Roman aqueduct used for 1900 years and still standing.

A former steam-powered mill from the 1800s is now an industrial park with a giant steel dragon slide.

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

The world's largest wooden structure.