A geological oddity formed by two rivers carving out a mass of limestone on both sides.

The show pony of cave systems, Fantastic Caverns manages to live up to its name.

Tucked away between two 19th-century buildings, this small shop specializes in the macabre.

A historic house in St. Louis was plagued by a series of suicides committed by family members involved in a successful brewery.

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

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

This abandoned prison castle has become an imposing gallery of graffiti art.

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

A museum to a cave explorer whose tragic death was a media sensation, and whose corpse became a tourist attraction.

Origin of the blue-skinned Fugates of eastern Kentucky.

An enormous natural sandstone bridge in Kentucky.

This former tuberculosis research hospital endeavored to cure the dreaded disease with fresh air and positive attitudes.

This limestone outcropping was once a ceremonial site for ancient Native Americans.

The site of the one of the most deadly train wrecks in American history.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.

Railroad came. People came. Railroad left. Town died.

Visit this playground of waterfalls, caves and sinkholes.

More than five miles of underground passageways.

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

Better known as the "Body Farm," this unique research facility has been studying how human bodies break down since the 1980s.

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.

Home of an evil witch famous within southern folklore.

Hidden amid the old-world charm of Savannah is a museum dedicated to the world of oddities and criminal history.