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.

A place to see how French aristocrats lived in the early 1900s.

For hundreds of years, automatons moving to metallic music have been marking the passage of time.

According to a local legend, this peculiar mountaintop rock formation is actually a demon that was turned into stone.

A fortress on this island housed the mysterious prisoner known as the "Man in the Iron Mask" for more than a decade.

The ruins stand as a somber reminder of France’s worst civil catastrophe of the 20th century.

Lady Liberty's original designer installed a little clone in this French fountain.

The world's largest reflecting pool is just two centimeters deep.

Balconies that have a most unusual accent.

Underneath this Byzantinian church lies a necropolis filled with ancient tombs and the ruins of previous churches.

Sofia's legislative center is continuously reinventing itself.

A vast Communist-era exhibition space in the Bulgarian capital.

A flamboyant five-story building in Bulgaria resembles a crawling snail.

A collection of art from Bulgaria's time as a communist state.

A spectacular Bulgarian cave resembling a devil's head with a waterfall rushing down its throat.

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.

This historic black and white monastery is one of Bulgaria's architectural jewels.

An architectural marvel that spans the Arda River, and has stories of a haunted past.

There's a mini version of Iguazu Falls hidden in the Balkans, and it's got a rope swing.

Bridge that died in war and was resurected.