Stuck in the middle of a modern Madrid city block are the remains of a 19th century sports complex.

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

This fascinating and poignant museum chronicles every imaginable aspect of Spanish colonialism in the Americas.

An early 20th-century bullring converted into a modern shopping center.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

This century-old ruined temple was reborn as "The Church of Skate."

A medieval village holds a very modern hotel.

Famed architect Antoni Gaudi built this generous thank you gift to a friendly host who housed him during a job.

"Alleys of Stone" form natural mazes in Spanish natural park.

An eccentric collection of antique items shares space with a prop-quality witchcraft museum.

A site where “the ravages of the war are more striking…than any other place in contemporary Spain.”

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.

One of Antoni Gaudí's least-visited works, an homage to Catalan patrimony that mixes neo-Gothic with Modernista forms.

Abandoned Nazi train station turned underground astroparticle laboratory.

This funky former tobacco factory is one of the most striking examples of Madrid's cultural diversity.

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

This awesome Spanish castle is so fantastical it was actually used on Game of Thrones.

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

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

A living art gallery painted on a canvas of Monterey pine trees.

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

Medieval ruins nestled within a breathtaking swath of Spanish nature.

The deserted remains of a luxury hotel turned hospital ward.

A landscape decorated with enormous skull sculptures.