In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A collection of objects supposedly singed by the hands of souls in purgatory.

2300-year-old Roman road connecting the empire.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

This demon atop the Notre-Dame de Paris looks utterly bored.

The location of this small park was once the site of an infamous public morgue.

A phantasmagoric tomb honors a Belgian artist-scientist's contributions to the world of spooky entertainment.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

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

A famous burial ground with a history both grim and literary.

The cedar tree in Highgate Cemetery earned its title by accident.

Mary Kelly was last seen here before she was murdered by Jack the Ripper.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

The sixth of London's "Magnificent Seven" cemeteries, and a source of unlikely inspiration to Beatrix Potter.

This coffee shop lies hidden beneath a historic church.

The quaint little store that is said to have inspired a famous Dickens novel was only given its name after the book was released.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

This museum inside Amsterdam's largest cemetery explores how people deal with death.

This impressive collection of rare books on ancient mysticism inspired author Dan Brown.

A curious collection dedicated to human and animal anatomy and pathology.

Cat art as far as the eye can see.