Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

The first green space constructed on an elevated viaduct.

How did a French journalist’s grave become the sexiest statue in the cemetery?

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

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

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

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

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

This off-beat, quirky communism-themed bar isn't afraid to poke fun at its history.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

A unique underground structure dating back to the 1st century BC.

This ancient theater was once the home of fierce gladiatorial battles.

A museum devoted entirely to the rattlesnakes and snake-related art.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

A museum dedicated to the alleged Roswell Incident.

Huge abstract sculptures of the Puerto Rican Flag.

This abstract sculpture is rumored to cast a hammer-and-sickle shadow once a year.

Illegal drag racing two stories beneath Chicago’s streets.

This bronze sculpture on a former squash court marks the secret origins of the Atomic Age.

Once called the "Polish Gold Coast" it is an icon of the neighborhood that bears its same name.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

The site of the first couple's first kiss is commemorated by the most adorable presidential monument ever.

A Bibliophile's Dream.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.