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

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

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.

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.

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

Urban explorers embraced America's now demolished first suburban mall, south of Chicago.

The history of funerals and funerary customs.

Once known as the Illinois Asylum for the Incurable Insane.

What was once one of the country's largest confectionary plants is now an abandoned ruin, but is still pretty sweet.

A century-old network of freight tunnels underneath the city's historic business district.

This former nursery supplied plants for the creation of Chicago's largest park.

This unassuming city park is home to three different types of Native American mounds.

A collection of 11 million buttons illustrates the human toll of the Holocaust.

A Japanese temple, old German townhouses, and public chess tables offer a peaceful escape from the bustle of the North Side.

In the Shawnee National Forest, amazing rock formations peer through the treeline.

Cold War missile launch site which has been converted to a public park.

This abandoned 19th century orphanage started as a boarding school for children of Civil War veterans.

In the loving memory of a tragically deceased role-player this Illinois park is decked out with both dungeons and dragons.

A river with some unusual, and occasionally dangerous, habits.

Eclectic collection of rare and beautiful stones in a historic home.