Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

"In the Dark" Restaurant in Paris offers dinner in complete darkness.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

A haunting collection of the vanished and disappearing natural world.

A unrivaled and rather horrifying collection of wax dermatological models.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

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

Notorious artist squat renovated into legal studios.

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

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

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

A collection of unique outdoor sculptures surounded by the beauty of nature.

An abandoned asylum where patients have been forgotten but their possessions remain.

Historic psychiatric asylum and most-filmed location in the Great White North.

The church is gone, but the graves and legends remain.

Hundreds of numbered stakes hidden in the woods mark the graves of the lost souls of a nearby asylum.

Decades after testing the polio vaccine on unwitting patients, this historic mental hospital sits in ruin.

This historic graveyard monument is dedicated to a tragic victim of witch trial hysteria.

Memorial of the Salem witchcraft hysteria in the town of Danvers, where it all began.

Located just behind a quiet residential neighborhood, this is ground zero for the Salem witchcraft hysteria of 1692.

This man-made mound monument was built out of soil from all across the Polish empire.

The inspiration for H.P. Lovecraft's horror stories and Batman's Arkham Asylum is now a condominium complex.