Origin of the blue-skinned Fugates of eastern Kentucky.

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

This road in the Great Smoky Mountains was supposed to assuage a displaced community, but ended up a $52 million dead end.

A stunning, abandoned limestone quarry in southern Indiana provided the stone to erect the Empire State Building.

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

Kentucky, Tennessee, and Virginia meet at this point in the Cumberland Gap.

Outstanding collection of 19th century medical instruments includes a life-size figure cast from as many as 200 cadavers.

This boulder stays on its mountain thanks to a huge chain and on the map due to local legend.

The longest navigable underground river in the United States is home to countless blind and albino animals.

148 feet long and in the middle of a verdant forest.

The only freestanding table rock formation east of the Mississippi.

Part of a worldwide art project, this mysterious semicircle of concrete shapes holds the pieces of a larger story.

Kentucky's anomalous peninsula projecting into the Mississippi River, site of legendary earthquakes and local feuds.

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

Planes, trains, and automobiles have all been sunk as attractions at this Illinois diving spot.

River pirates, murderous bandits, and serial killers used this Illinois cave as their debauched hideout.

An enormous natural sandstone bridge in Kentucky.

A bizarre roadside attraction and the first instance of miniature golf in the world.

Famous for its bio-luminescent inhabitants, known as "dismalites."

Once decrepit and slated for demolition, now one of the longest pedestrian bridges in the world.

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

More than five miles of underground passageways.

Prehistoric animals decorate this popular outdoor park.

The world's longest known cave system.