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

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

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

Spain's stunning solar energy plant.

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

A 16th-century Andalusian palace.

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

The world's largest wooden structure.

An iconic photograph from the Spanish Civil War saved this shrapnel-scarred historic house from destruction.

This species of wild goat stars in witchy legends and frolics among the park's eerie rock formations.

This small and often-overlooked museum holds some of Spain's finest artistic treasures.

This lucky bronze frog was gifted to Madrid by a casino.

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

The only urban monument in the world designed by the great surrealist painter Salvador Dalí.

The earliest known map to show America, discovered by accident at a Paris bookshop.

A lush indoor jungle fills this bustling Madrid transportation hub.

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

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

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.

One of Europe's largest supercomputers is housed inside of a disused chapel.

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

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

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