The largest natural travertine bridge in the world is nestled in a small canyon in central Arizona.

This 40-room dwelling tucked within a cliff was built by the basin's prehistoric residents.

An off-the-beaten path cave with an underground lake.

The Magical World of George Phar Legler.

One of the largest open-pit copper mining operations in the entire country.

America's only nuclear missile silo open to the public.

The biggest solar telescope in the world helps reveal the secrets of our sun.

A strenuous, unofficial trail leads to spectacular views in one of America's most remote national monuments.

Let Ouray’s tallest waterfall sweep your breath away on a dealer’s choice of scenic hikes.

A recreation of an Old West apothecary full of curios.

No one knows exactly how deep the world’s deepest geothermal hot spring is.

A futuristic hovertrain is parked unceremoniously alongside a nondescript road.

This razorback ridgeline has doubled as a scenic drive since the early 1900s.

A renovated hotel is bringing new life to a nearly-abandoned mining town in Colorado.

The narrow mountain road that carves a path between Florence and Victor is tied to ghost towns and ghost stories.

Community owned and operated, this property is home to a diverse set of nudists.

This now-abandoned outcrop is an important Native American spiritual site, overtaken by European settlers and mining pollution.

Where scientists keep miles of very valuable ice from Antarctica and Greenland from melting.

A multiversal transit station located right below a highway interchange.

Paranormal experiences in this hotel's room 217 led Stephen King to write "The Shining."

This tea house was a hand-built gift from Boulder's sister city in Tajikstan.

The clock that sets them all.

The largest self-built castle in the U.S., six decades in the making.

This small museum contains fossils from an era when Kansas was underwater.