400 million-year old limestone caverns nestled in the Ozarks served as shelter and a hideout for cultures throughout North American history.

This unattributed sculpture in Amsterdam is hiding in plain sight.

Christ's blood preserved in a Belgian town.

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

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

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

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

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

The highest point in Washington state is a volcano covered in glaciers.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

Speak to a companion on the other side of the room loud and clear through this architectural anomaly.

Stroll through a wonderland of stupendous moss-covered trees.

One of Savannah's oldest and most haunted cemeteries, featuring graves desecrated by Sherman's Union Army.

If all members were present at the table, a sixth of the world's wealth would be under the same roof.

A cathedral resurrected from the ashes of one of Europe's greatest urban fires.

A vast array of tropical plants collected by a vacationing couple.

One-time winter retreats of prolific inventor Thomas Edison and his friend Henry Ford.

Charleston's historic city jail once held everyone from pirates to Civil War POWs.

A beautiful 62-acre Catholic shrine and botanical garden.

This former coal gasification plant found a curious second life as a popular public park.

A luxuriant botanical garden below sea level.

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

A century-old hotspot for jazz, frequented by everyone from Charlie Chaplin to Al Capone.

A lush green oasis in the middle of Chicago.