This structure among the trees was the result of divine inspiration.

Mile-long cave system near Great Smoky Mountains.

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.

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

Enormous lake at the bottom of a unique cave system.

This roadside attraction in the woods of Mississippi is a scalable replica of the Holy Lands during biblical times.

This two-room shotgun shack in Tupelo is the birthplace of a King.

William Faulkner kept his beloved estate wild and untamed.

Built by prisoners of war, the largest small-scale model ever built includes eight miles of tiny streams that now sit abandoned.

An eerie and beautiful group of columns mark the site of a grand mansion lost to time and fire.

A Muppet museum in small-town Mississippi honors the roots of Jim Henson's most beloved creation.

Eclectic collections, artwork, and some feline friends fill the writer's former home.

Naturally formed white marble arch housed in an abandoned marble quarry from the 1800s.

These beautiful ruins deep in the Pennsylvania woods are thought to have been a ski lodge or a speakeasy, but no one really knows.

The only way to see Pittsburgh is from the top of this lookout point, just like the ancient members of the native peoples did.

One of the steepest streets in the United States makes an intriguing challenge for cyclists.

The universally beloved children's television figure is interred on a high hilltop in one of western Pennsylvania's oldest cemeteries.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

Designed as a place for patients to take in the scenery, this tower has a dark history.

The house where Rudyard Kipling wrote 'The Jungle Book' is also the location of the first tennis court in Vermont.

The remains of one of the last mining camps developed on the New River.