One of the most scenic stretches of road in America winds between some of the country's oldest trees.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

A beautiful geyser under environmental threat.

This shop for all your super spy needs hides an educational secret.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

A bizarre house filled with an astounding array of collections.

The first public building in Savannah to offer air conditioning was a luxurious cinema that still operates today.

One of Savannah's oldest and most haunted cemeteries, featuring graves desecrated by Sherman's Union Army.

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

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

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

It was once the base for a series of domestic terror attacks.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

The house where John Wilkes Booth conspired with his co-conspirators.

Controversial tribute to the heavyweight champion boxer who grew up in Detroit.

The concrete shell of an industry giant remains as a playground for graffiti artists, auto scrappers, and paintball warriors.

One man's attempt to create an artistic wonder on a run-down block in Detroit.

The bones of an old zoo crumbling in the shadow of a new one.

A Beaux-Arts triumph set to become Ford's innovation campus

A museum dedicated to the history and exploration of both popular music and science fiction.