A fantastic castle rumored to be the birthplace of King Arthur.

Geological storytelling.

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

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

A celebration of solstice followed by a fiery purging of evils.

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

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

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

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

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

A small church ornamented with medieval erotic sculptures.

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

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

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

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

Commonly acknowledged as the only public monument to the Devil himself.

This underground church is topped with a 500-foot cross that is seen by many as a beacon of fascist hubris.

The mysterious large white cross visible from the runway is a memorial to a massacre during Spanish Civil War.

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

The world's largest collection of ships in bottles.

From Tintin to the Smurfs, Europe's greatest graphic icons are celebrated in a grand Art Noveau gallery.

At Monet's beloved home you can still see the Japanese bridge, waterlilies, and weeping willows that were the subjects of some of his most iconic paintings.

Abandoned Nazi train station turned underground astroparticle laboratory.

Historic medieval fortified city in southwest France.