The site of a 19th century "dream city" that almost rivaled Chicago before being swallowed by the Indiana sand dunes.

A turn-of-the-century architectural marvel built on healing mineral springs and salt licks.

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

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

A humble homemade ride attracts visitors from around the globe to this small Midwestern town.

You can climb to the summit of Black Mountain, as long as you sign the waiver.

Mysterious ancient boulder carved with petroglyphs in the mountains of Western North Carolina.

An unknown Hall of Fame in Jackson, Tennessee.

Over a dozen Native American earth mounds dating back over 2,000 years dot this Tennessee archaeological park.

This vast kitty-themed collection illustrates the history of human-cat interaction.

This calm grassy field was once a Superfund site full of thousands of nasty chemicals.

You'll need cowboy boots to trek to this old-fashioned saloon nestled in a giant natural cave.

The perfectly named cave drop is the deepest in the continental United States, almost matching the height of Seattle’s Space Needle.

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

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

One Confederate statue that accurately reflects the ugliness of its subject.