The largest underground church in Europe.

The beautiful bas-relief lines a sliver of a 19th-century walking path between two charming French villages.

Islanders once used this dramatic, otherworldly landscape to hide their cattle from Viking raiders.

An Irish town has built a statue to a silent film actor simply thanks to the holidays he once spent there.

A French valley with forests so lush it was nicknamed "the Small Amazonia of the Pyrenees."

This narrow path was cut right into a French mountainside to feed the country's early naval expansion.

Abandoned Nazi train station turned underground astroparticle laboratory.

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

A series of recreated fortifications mark George Orwell's path through the Spanish Civil War.

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

Hundreds of stone stairs and a winding medieval bridge connect this haunting Spanish island to the mainland.

One of the world’s longest pedestrian suspension bridges.

One of the largest Roman settlements in Portugal.

This museum documents the ancient practice of salt production in Figueira da Foz.

A medieval church with largest and oldest collection of Renaissance frescoes in France.

An arresting arch punched straight through a mountain provides one of the most scenic spots, and challenging climbs, on the planet.

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

Numerous sculptures set along hiking trails symbolize and idealize the relationship between man and nature.

To fit bodies into this Renaissance crypt, they were first left to decompose in the crypt's rotting room.

An outsider folly near Madrid.

Whether they are bulls or pigs, these ancient animal sculptures are fascinating relics.

An old wool-washing house filled with Fluxus contemporary art.

This small Spanish village is home to dozens of public paintings meant to trick the eye.

This medieval chapel is now a shrine to the region's favorite sport.