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

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

Beautiful tiles decorate many of the town's surfaces and stand testimony to its glorious artistic history.

A micro-communist utopia in Spain with no police, no mortgages and full employment.

A contemporary art installation housed within a Gothic cathedral.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

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

Haunted tuberculosis hospital built by the patients.

A network of hundreds of interconnected wineries in caves hides under the town center.

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

For one day every month Barcelona's Estació de França transforms into a market for model trains.

The Gaudí-inspired building that was the start of Terrassenc modernism.

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

The former 1920s mansion of a prominent Catalan developer was used as the Soviet Embassy during the Spanish Civil War, and there is still a bunker below the garden.

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

The Cathedral of Salamanca has a number of unusual carvings but none so surprising as a modern astronaut.

This remarkable prehistoric town is full of watchtowers and houses that have withstood thousands of years.

This "flat geyser" bubbles up out of the ground periodically like a disappearing river.

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

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

An abandoned Indian-inspired mansion.

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

On La Gomera, "Silbadors" communicate in a 4,000-word language of whistles.

This religious complex carved into a cliff is steeped in legends of miraculous stags and the Holy Grail.