Operational for less than a year, this mill produced more than 11,000 tons of chrome concentrate in its short lifespan.

Derelict buildings are all that remain of a complex at the site of one of the worst mining disasters in Montana history.

The last physical evidence of the Lewis and Clark trail is one of their autographs etched into this giant rock.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

Thanks to a loophole in property ownership, this alleyway has become a cacophonous street gallery.

One of America’s oldest and spookiest hotels, thanks to the residency of ghosts, dead presidents, and Alfred Hitchcock.

Every president in history is immortalized in bronze in downtown Rapid City.

South Dakota's oldest operating brewery is housed inside a historic firehouse.

A fitting attraction for the corn capital of the world.

The maximum security facility was once thought to have "the bloodiest 47 acres in America."

European castle ruins in an American state park are actually the product of death and grief.

Like Stonehenge, but with boats and oodles more charm.

Quirky water tower advertises the long-gone Brooks Tomato Products Co.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

Curious cave that stays a cool 56 degrees all year long.

A sculpture of a giant man escaping from the depths of the Earth.

The Old Courthouse takes visitors on a captivating trip through St. Louis' timeline.

A plaque on the side of a parking garage marks the burial place of a great Ottawa chief.

One of the world's earliest skyscrapers.

A creepy sculpture of a decapitated head invites viewers to see St. Louis through its empty eyes.

The only Florida state park with publicly accessible caves.

Four, 18-foot-tall badminton shuttlecocks lie scattered about the lawn of a Kansas City museum.

A humid oasis combines recreation with exploration in a unique underwater cavern.

Come for the boats, stay to explore the intriguing assortment of art.