The Roman city was the birthplace of various emperors and is home to one of the empire's most impressive architectural feats.

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

Two towns are linked by an engineering marvel masquerading as a boring suspension bridge.

The unexpectedly beloved remnants of a controversial thermal power plant.

A reproduction of the famous prehistoric cave paintings is hidden underground at the National Archaeological Museum.

Giant topiary dog once played a role in a terrorist bomb plot.

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

Geological storytelling.

12th-century holy complex shares land with a natural park full of heavenly waterfalls and raptors.

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.