Beneath the city of Lourdes, France is a massive, concrete church.

Abandoned 18th century weapons factory in the Aezkoa Valley.

This futuristic observatory at the top of the Pyrénées offers unrivaled views.

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.

Sanctuary on a ridge near an ancient shrine to a "Black Madonna" built by the founder of Opus Dei.

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

32,000 tiny soldiers are posed in 23 historical settings.

Balconies that have a most unusual accent.

An often-shuddersome journey into a low-tech, robotic themepark.

Longest canal tunnel in the world, abandoned in the 1960s.

A British plaque explains that a house was built using the spoils of the first international golf bet.

This historic Benedictine monastery brews a booze so toxic that it has often been blamed almost singularly for Scottish hooliganism.

This haunting stone chasm is a hotbed of mossy rock and English legend.

The true age of this ancient stone circle is unknown, but its stunning vista isn't in question.

Created hundreds of years ago, the magical follies and landscapes at this park were almost lost to time before being restored.

Seat of the Duke and Duchess of Devonshire for centuries.

This logic-defying 16th-century Tudor manor still stands to the delight and astonishment of onlookers.