An abandoned socialist utopia built in the late 19th century.

Originally slated to become a luxurious resort, this structure is now a graffiti haunt reclaimed by nature.

The oldest operating roller coaster of its kind, the Montaña Suiza has been thrilling riders since 1928.

This abandoned naval battery stood at the ready as recently as the 1980s.

This historical manor is complete with a magnificent garden.

Behind this unmarked facade lies the original bomba—a crunchy orb of fried mashed potatoes stuffed with minced meat.

Abandoned tunnels dug for the once-thriving sea salt industry on the coast of southern Spain.

Haunted tuberculosis hospital built by the patients.

Despite its grandiose name, this enigmatic first-century void under the town is no cave, and it's possibly not a palace either.

An ornate tower shows off a local artist's architectural flair.

In Spain, the ruins of a Roman military camp sit along a flooded section of a river.

Locals use these rock pools and waterfalls for swimming and cliff diving.

The remains of an encyclopedic sculpture garden later used as an internment camp.

The unfinished final resting place of some of Spain's most prominent politicians.

The ruins of a bombed medieval village memorialize the destruction of the Spanish Civil War.

This 47-story "M" needed 20 years to be completed

This ancient tunnel is one of the most important examples of Roman hydraulic engineering in Spain.

This art installation at an abandoned lipstick factory has distinct anti-capitalist vibes.

Religious dwelling in a Spanish volcano.

A five-square-mile slice of Spain on the Mediterranean coast of North Africa.

Lava stone structures possibly dating back to the 19th century may have been a stopping point for voyagers between ancient Egypt and the Mayan Civilization.

This Arab fortress was once the largest citadel in Western Europe.

This underwater graveyard commemorates a group of murdered 16th-century missionaries.

"Satisfying" is a good way to describe these beautifully aligned rows of Spanish mills.