Italian cave with exceptional acoustics and an unsavory history.

A monument to the migrants who cross the dangerous waters between North Africa and a tiny Italian island.

The housing complex served as an anti-fascist fortress during the Austrian Civil War.

Once a 19th-century brasserie, this McDonald's exterior celebrates Alsatian design and the "King of Beer."

Walk through spectacular aisles of hanging meat and wagon wheel–sized cheese at the world's largest wholesale food market.

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

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

An immersive projection art installation uses sound, scale, and light to take visitors inside classic works of art.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

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

Notorious artist squat renovated into legal studios.

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 three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

The walls are decorated with whimsical murals painted by the creator of the Madeline franchise.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

This unique architectural wonder is home to luxury apartments.

A symbol for the opposition to nuclear power around the world.

A natural wonder in south Denmark.

A little-known cafe in an old copper bridge tower with 360-degree views of the harbor.

This ultra-modern wooden boardwalk turns the ocean into a swimming pool.