Crumbling World War II-era gun emplacements still stand near lighthouses on the Spanish coast.

This modernist bridge highlights the bear as a symbol of Madrid.

This 18th-century pond is one of the main attractions in the Jardín del Príncipe in Aranjuez.

The oldest vestiges of Madrid found here, have been incorporated into this new museum.

Built in 1925, this glass-roofed shopping arcade is known for its modernist Italian architecture.

The largest and best preserved necropolis in the Western Mediterranean.

These ruins are all that remain of Tortosa’s lost coal gas manufacturing industry.

Hidden under a center for the elderly are the dungeons which were used during the Spanish Inquisition.

An Antoni Gaudí masterpiece in Astorga.

The remains of a convent turned military barrack in the heart of Madrid.

In this 400-year-old hotel in Madrid, you'll find a comb in every room, an old clock, and maybe a ghost.

Once used to calculate the various levels around the country.

An abandoned 6th-century monastery features a medieval map of the known world.

Designed in the Romanesque style, this structure was once a fortress monastery.

This tunnel was built in order to protect the village of Daroca from flash floods during rainy seasons.

Hidden underground, a remarkable 10th-century bath complex survives virtually unaltered.

The world's largest single-aperture telescope resides in the Canary Islands.

A long strip of fossil-filled limestone makes up this natural bridge above a rushing stream.

Barcelona's only remaining tram system takes riders to the Tibidabo funicular.

The final resting place of the great navigator, or maybe his brother.

This 15th-century aqueduct with distinctive pointed arches was used for irrigation in the Vinalopó valley.

Two 2,500-year-old Phoenician boats found on the coast of Spain, giving incredible insight into the ancient maritime traders.

A living time capsule of the 1960s Richardson Bay water-front.

Factory that once supported an entire company town of 350.