Could this grave be the true resting place of legendary gunfighter "Doc" Holliday? Unclear.

The remains of one of America's first radiation testing grounds still rest ominously in a Georgia forest.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

An 18th-century Spanish watchtower made entirely of seashell and concrete.

Despite being made of a seashell mortar, the crumbling remains of this historic Florida mill are still standing.

Town of spiritualists and mediums in Florida.

The grave of America's 11th president is not in some grand monument but instead it's hidden away on the grounds of the Tennessee Capital.

Knoxville’s architectural icon was the symbol of the 1982 World’s Fair, even catching the googly eye of Bart Simpson.

All you ever needed or wanted to know about America's favorite whiskey, but not a drop to drink.

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

The oldest operating Mississippi River–style steamboat still navigates the Ohio River.

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

The world's longest known cave system.

Look closely and you’ll notice that the color changes a third of the way up the tower.

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

Behind an abandoned storefront is an example of pioneering 1930s gas station architecture.

A historic Civil War estate-turned-museum looks back on the Confederate States of America.

A 56-foot tall statue of the god of fire looks out over Birmingham, Alabama.

A serene plaza that commemorates one of the Granite State's most iconic figures.

A town wears its heart on the sleeve of a smiling girl, arms flung wide open in a cheerful greeting for all who encounter her.

Come for the gun-toting hillbilly madman, stay for the ice-cream loving basketball bears.

A short nature trail winds through the greatest works of poet Robert Frost.

According to the experts at the Guinness World's Record office, this is the longest candy counter in the world.

The highest point in the state of New Hampshire, and while unlikely "the worst weather in the world," it sure seems that way to hikers.