A magnificent, long-abandoned castle built in the wake of the reconquest of Spain.

These magnificently sculpted tombs represent Spain's own legendary version of "Romeo and Juliet."

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

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

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.

Hidden well off the beaten path in Catalonia is this crumbling medieval castle that is slowly being covered in graffiti.

This huge abandoned fortress hidden inside a mountain holds a world of subterranean secrets.

This chest hospital with a dark, haunted past serves as a fitting set for horror films and a paradise for ghost hunters.

This embalmed man is one of the best preserved mummies from the Canary Islands.

The largest prehistoric cemetery on the Balearic Islands dates back over 2,500 years.

Mysterious face-like images that appeared within an Andalusian house are surrounded by legends of the paranormal.

This small museum tucked within a subway station holds pieces from Madrid's past.

An impressive display of ships and artifacts from the ancient Mediterranean maritime trade.

This beautifully verdant lagoon is tucked below a massive volcano in a crater atop a black pebble beach.

Part of the medieval watchtower is displayed in an otherwise ordinary parking garage.

This imposing modern citadel started out as a home renovation project.

An abandoned Indian-inspired mansion.

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

Remarkably intact Roman stone fortifications have encircled this Spanish city for centuries.

An ancient Roman theatre restored to its former glory in the Spanish city of Cartegena.

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

This ancient Spanish castle sits high upon a hilltop.

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

The oldest Roman lighthouse still in use.