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

One of the largest ossuaries in Spain is packed from floor to ceiling with bones.

Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

Occupied for six centuries by Franciscan Order nuns, this monastery is an amazing ode to Catalán Gothic architecture.

This former charity hospital for elderly clergy houses some of Seville’s most treasured paintings.

Its appearance in "Game of Thrones" may spur on the long-awaited restoration of this medieval shipyard.

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

This massive fiberglass Gulliver turns every visitor into a Lilliputian.

This awesome Spanish castle is so fantastical it was actually used on Game of Thrones.

A Franco-era dam flooded (almost) everyone out of this centuries-old Aragonese town.

A charming Spanish village sits atop this natural limestone overpass.

A 16th-century Andalusian palace.

The abandoned ruins of a beautiful medieval castle just outside Barcelona.

The chefs at El Diablo use heat generated by an active volcano to cook the food.

An open-air "garden" of mural art that changes weekly.

Stunning Roman aqueduct used for 1900 years and still standing.

A gravity-defying "devil's bridge" that has a surprising architectural feature for its stability.

This funky former tobacco factory is one of the most striking examples of Madrid's cultural diversity.

A Spanish town built into the cliffs.

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

This stunning iron gate designed by Modernist architect Antoni Gaudí is filled with mythic symbolism.

This Navarrese cave's history of witchcraft and pagan ritual is not just embraced, but recreated each year.

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

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