A 2017 crowdfunding campaign saved this historic castle from being destroyed.

Beautiful carved tunnels.

A self-built mosaic house and sculpture park.

This 12th century, partially destroyed, abbey has had several owners and was seized during the French Revolution.

One of the oldest and largest wooden churches in France was very evidently constructed by shipbuilders.

Deep in the limestone cliffs of the Alabaster Coast, a German fortress built during World War II.

If you look closely at the oldest bridge in Paris, you might notice hundreds of ugly faces leering from its sides.

The tombstone of an unfortunate explorer who disappeared in the Paris Catacombs.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

Stripes of human ashes cover a back lawn in the most sought-after burial grounds in Paris.

Indents in the pavement are all that remain from a grisly death machine in Paris.

An immersive projection art installation uses sound, scale, and light to take visitors inside classic works of art.

A melancholy jester sits on the grave of a famous 20th-century ballet dancer and choreographer.

Former hunting lodge of a duke who was an avid collector of impressionist works.

One of Jeff Koons’s largest sculptures and his first commemorative work.

Executions were once held near this beautiful 18th-century fountain.

A tribute shrine where the Space Invasion street art movement started.

This natural French spring has been turned into a magical grotto by Roman and medieval constructions.

One of the largest barracks of the Austro-Hungarian monarchy's military is now an abandoned ruin.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

Legends surround an ancient tree trunk riddled with nails for good luck.

Baroque celebration of the end of the Great Plague of Vienna.

Extremely famous in his native country, this Cracovian painter is all but unknown beyond Polish borders.

The 700-year-old fortress was the site of Count Orlok's castle in "Nosferatu."