Site of a classic 19th-century physics experiment to prove the earth is rotating.

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

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

This modest marker near Notre Dame identifies the very center of Paris.

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.

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.

This Viking gravestone carved in a rare runic style was dug up from a London churchyard.

A portly statue of a golden boy commemorates an unusual cause of the Great Fire of London: the sin of gluttony.

The taxidermied remains of a once-great parrot.

The last four extravagant street signs of London's historic banking street.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

Spitalfields' regal market goat is said to be a monument to the area's migrant population but most are pretty sure it's just a goat.

The remains of the great moral philosopher reside in a university in London.

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

Two plaques commemorate the site of Shakespeare's first theatre.

Bronze sculpture celebrating the relationship between Churchill and Roosevelt.

Pop culture has helped to keep this iconic British building from being destroyed.

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

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

A cluttered and astounding collection of antiquities and curiosities.