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

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

The very center of Paris is surrounded by a bevy of strange good luck rituals.

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.

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

Notorious artist squat renovated into legal studios.

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

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

Pulled from the rubble of one of the worst modern tragedies, a steel crossbeam became a symbol of hope for New Yorkers.

You can still ride this 100-year-old work of art in Brooklyn's largest public park.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

Lady Liberty's first beacon of enlightenment is now displayed in a museum near the statue.

Sniff the Titan Arum's rotting flesh.

Mysterious 500-year-old tapestries depict a unicorn hunt.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

New York City's smallest piece of private property.

World-famous, Pink's still manages to keep its prized cult fetish status.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

America's most famous piece of self-built architecture.

Since 1874, this macabre collection has developed into a museum devoted to Scotland Yard's mementos of dastardly deeds.

The medieval woodcut-style artwork chronicles life in medieval London.

A mysterious shape catches the eye in this 16th-century painting.