Ancient paintings known as the "Sistine Chapel of Cave Art."

Among Europe’s most spectacular Ice Age painted caves still accessible today.

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

Trek into the depths of the cave where 17,000-year-old paintings exist alongside 400-year-old graffiti.

Historic medieval fortified city in southwest France.

For a brief time in 1960s France, families could climb into a tiny submarine and be pulled along an underwater journey.

Sometimes an island, sometimes a rocky outcropping connected to the world by a tiny suspension bridge.

It may take some time to locate, but it's sure to warm even a heart of stone.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

More than five miles of underground passageways.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

A 24-hour vending machine restocked daily with homemade full-sized pecan pies.

Old car parts and assorted materials get turned into one man's mechanical treasures on the side streets of Cleveland.

Rare recess caves fill this unbelievably beautiful Ohio park.

The trials and tribulations of marking Poe’s grave.

The highest point in Maine is a grand gift to the state citizens that also happens to be one end of the Appalachian Trail.

A whimsical monument marks the highest point in Kansas, not that you could tell by the looks of it.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

Two thousand artifacts from around the world collected by one woman who loved to travel.

This crumbling industrial fortress has attracted daredevils, filmmakers, and historians.

The only example of a Paris Métro sign in use at a subway station outside of the French capital. 

The vaulted ceiling is home to a scurry of “squirrelgoyles.”

Small ship votives hang from the vaulted ceiling of this port-side church with a Latin inscription on the wall.