A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

This massive library holds what was once the largest book collection in the world.

Notorious artist squat renovated into legal studios.

Abandoned railway line circling the city of Paris.

France's most famous cemetery, with some of its most curious tombs.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

This black sand beach was crafted from volcanic explosions including the historic Minoan eruption.

These sea caves are the source of Xigia Beach's distinct aroma.

The partially submerged ruins of a white marble quarry used in ancient Greece for over 1,200 years.

This slumbering beast honors the Bavarian soldiers who died in Greece during a 19th-century typhoid outbreak.

According to legend, this cavern holds the passage that Persephone used to travel to and from the underworld.

Step inside an ancient beehive tomb built for a mysterious cult hero.

Overlooking the harbor is a beautiful neglected mansion guarded by two Egyptian sphinxes.

This ancient statue of Dionysus lies unfinished and abandoned in one of Greece's oldest quarries.

A magical, if a bit tacky, 1960s castle conjures up medieval fairytales and Greek mythology.

This little-known, 35,000-specimen collection in Greece is a lepidopterist's dream.

A sprawling collection of books and manuscripts about ancient Greece that would have put their famed libraries to shame.

Ruins of a 13th-century fortress perched above a breathtaking Mediterranean bay.

A little-known park with unusual, half-ruined structures and a mystical energy.

This open air archeological site houses almost as much wildlife as it does classical religious artifacts.

One of the largest single-span stone-arch bridges in the Balkans looks like something straight out of a fairytale.

This famous archeological mystery may be an ancient example of movable type.

This abandoned Greek island was the last active leper colony in Europe.