This nearly endless university hallway is home to a unique sunset known as "MIThenge."

This hidden labyrinth offers walkers some brief peace of mind.

A cemetery in Barcelona's Poblenou district is home to this touching funerary statue, which depicts death in the form of a winged skeleton.

Mysterious Spanish catacombs of unknown origins.

A Spanish forest is filled with mysterious stone carvings.

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

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

An unsettling shrine dedicated to the ravenous beast that prowled 18th-century France.

The mummified heart of Louis XVII, the lost dauphin of the French Revolution.

For over 300 years this little carving has been the city’s good luck charm.

The final resting place of the "father of special effects."

Green labyrinth formed by a karstic maze hidden in a preserved oak forest.

The construction of a tram line unveiled hidden remnants of the old medieval city.

Statue of a decomposing prince that once held his heart in its hand.

Hundreds of dwarf beeches create an unusual, haunting forest in the north of France.

Nicknamed the "Museum of Horrors," this French anatomical collection has been fascinating visitors for over a century.

A mud statue stands in the dark tunnels, seeming to hold up the weight of the city above.

An isolated 17th-century chapel on a remarkable site once dedicated to Celtic sun worship.

This collection of French root art looks like an indoor fairy wonderland.

The personal library of the founder of modern neurology is open to visitors.

Hundreds of secret cabinets built into the walls of legendary poisoner's private work room.

Sleep in a climate-controlled plastic bubble for the night.

A beautiful and classically designed villa, with an hourly infestation of monsters.

The artist and his brother are buried in a landscape straight out of a van Gogh painting.