The ruins of an ancient Celtiberian town with incredible rock-cut buildings and a Roman aqueduct.

Spain's largest bullring offers a unique glimpse at architecture and history.

An outsider folly near Madrid.

Replicas of fossils unearthed during renovation work reveal how this area would have looked millions of years ago.

The fragmented remains of a massive public bath connected to the city's water supply.

One of Europe's largest groups of dolmens remains largely off the typical tourist track.

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

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

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

The extensive relics of an ancient Roman and Phoenician fish processing plant hide in a town park.

The cathedral of a controversial, conservative, schismatic sect that declared the Catholic Church heretical and founded its own succession of popes.

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

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

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

Semi-mystical manmade towers of rocks decorate this rocky seaside.

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

Religious dwelling in a Spanish volcano.

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

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

This beautiful spit of land was once the summer playground of the king of Spain.

Haunted tuberculosis hospital built by the patients.

An unexpected ghost village lurks on the southeast coast of Tenerife.

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