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

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

Notorious artist squat renovated into legal studios.

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

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

This massive library holds what was once the largest book collection in the world.

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

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

Isak Heartstone, a 15-foot wooden troll made out of recycled materials.

Each year, teams of the world's best snow sculptors have 65 hours to create frozen masterpieces.

Air Force Academy Chapel made of 100 identical tetrahedrons works to inspire those of all religions.

Climb to the top of this spiritual tower, and you'll be rewarded with spectacular views.

The highest paved road in North America winds its way up Mount Blue Sky in Colorado to an altitude of 14,130 feet above sea level.

When ecosystems collide in the arid Southwest.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

A breathtaking array of ancient Pueblo structures and artifacts counterintuitively preserved by neglect.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Paranormal experiences in this hotel's room 217 led Stephen King to write "The Shining."

Less a museum than a bizarre fantasy world created by artists and engineers.

This ancient settlement contains some of the largest earthen mounds in North America.