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

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.

Visit a surreal landscape so otherworldly NASA actually used it to train the Apollo 17 crew.

Of the many chalices in the running for the Holy Grail, this one in Valencia Cathedral sure looks the part.

This ancient Spanish castle sits high upon a hilltop.

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

Cliffside houses provide a spectacular view from their perch above the valley.

This house's itty bitty size means no humans allowed.

This Navarrese cave's history of witchcraft and pagan ritual is not just embraced, but recreated each year.

The studio of Catalonia's most famous theatrical designer remains exactly as he left it.

A lush indoor jungle fills this bustling Madrid transportation hub.

A museum dedicated to the Spanish occult in a town that was terrorized by the Inquisition.

An architect transformed this abandoned cement factory into his castle-like workshop.

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

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

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

A beautiful but toxic fountain of mercury.