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

Erosion and time have created a naturally-formed water park.

Curious cave that stays a cool 56 degrees all year long.

The world's largest man-made underground caverns offer unparalleled underwater wonders.

Once an ambitious nature spa, these forest ruins now provide a serene monument to failure.

European castle ruins in an American state park are actually the product of death and grief.

Hollowed out cedar log tubs set in an ancient towering forest.

This house proudly displays an interactive and continuously changing exhibit of lawn flamingos.

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

Most-visited and most-photographed slot canyon in the American Southwest.

Rippling sand dunes frozen in the Arizona rock.

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

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

Home of an evil witch famous within southern folklore.

Enormous lake at the bottom of a unique cave system.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

An otherworldly musical haven in The Big Easy.

A museum of unusual collections, mini-towns, and a half-dog, half-alligator.

Once defending the city of New Orleans from invasion by sea, this fort faces an uncertain future.

The only rotating bar in New Orleans has been slowly spinning since 1949.

This New Orleans tree is filled with hidden chimes that produce a carefully tuned melody.