The oldest stone house in Paris was built by its most famous alchemist.

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

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Abandoned railway line circling the city of Paris.

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.

An alchemist's "magic door" stands in the middle of a Roman park.

The yawning maw of this pagan visage is said to bite off the hands of liars.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Architectureal fantasy quarter of Rome.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

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."

A slice of central Asia in the middle of Berlin.

The most visited, and possibly most controversial, museum in Germany.

Started as a kitchen garden, now the second largest botanical garden in the world.

This strange seaside tower got its name from a wealthy eccentric who would hide coins among its stones.

Lured here by the promise of tens of thousands in gold, Jesse James started a quintessentially American trend of robbing trains in-motion.

Baltimore's first skyscraper may be home to the inspiration behind pulp fiction's most celebrated bird.

Crammed into a Baltimore row house is an oddities shop that sells everything from skulls to dead insects.

This free, take-a-book shop seems like a trick but isn't.

The site where Poe "in great distress, and ... in need of immediate assistance" likely died.