The farm where one of America's greatest leaders was raised is now a well-appointed landmark.

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

A 30-year-old Sycamore tree grown from a seed taken to the moon and back.

Once adorning a New York skyscraper, these reclaimed ruins now haunt an Indiana park.

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

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

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

A key producer of charcoal iron in the early 1800s, the structure still stands today.

This simple, broken column marks the final resting place of one of America's most famous explorers.

The small cave that housed Tennessee's "first citizen."

The first full-scale tunnel built in America is short but scenic.

The secret city built by the Manhattan Project.

More than five miles of underground passageways.

Mile-long cave system near Great Smoky Mountains.

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

This huge clock made of flowers and simple machinery was once used a political weapon.

The largest cemetery in Louisville is the final resting place of Col. Sanders and Muhammad Ali.

The only building in Louisville (hopefully) that contains two ancient holy skeletons.

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

A local scoured more than 1,000 acres for stone to create his masterpiece.

This grave marks the final resting place of a legendary frontiersman... unless it doesn't.

This abandoned cemetery has a dark past of bodies buried over bodies.

The grave of the iconic Kentucky Fried Chicken mascot features a bust of the man behind the goatee.

Rabbit Hash is a heaping slice of Americana from another era, with a very peculiar origin behind its unusual name.