Home to the "Rat King" of Nantes and other wonders of the natural world.

With a history of slaughter, feast, and famine, remnants of the pork industry decorate this area--even its church.

The headless bodies of more than 1,300 guillotined victims of the Reign of Terror are buried here in mass graves.

A haunting collection of the vanished and disappearing natural world.

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

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

Notorious artist squat renovated into legal studios.

If they push on just the right spot, even the weakest person can move this titanic boulder.

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.

Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.

Hidden away in a modern library are the remains of one of the 18th century's most celebrated wunderkammers.

A colossal sculptural lion built by the same man who designed the Statue of Liberty.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

The final resting place of the great navigator, or maybe his brother.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

It houses the remains of a 17th-century version of the Titanic.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

The convergence of two currents makes this a surprisingly pleasant getaway in the Arctic Circle.

Housing the famous Norwegian ice-defying 19th century polar exploration ship.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

Even France's favorite aquatic son Jacques Cousteau, couldn't get to the bottom of it.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.