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

The massive, incredibly rare instrument is over 11 feet tall with a range so deep it goes lower than humans can hear.

A towering bronze statue memorializes the founding father of postwar American conservatism.

A geological mystery on Camelback Mountain.

A self-built castle made by a mysterious man.

This collection of Wild West movie memorabilia also claims to hold some secrets of the Lost Dutchman's mine.

Stairs often replace streets on the steep slopes of this old mining town.

A mistaken marker makes an erroneous claim along the historic Old Divide Road.

An old saloon in the West filled with history, and according to some, a few dozen ghosts.

The world's largest rose bush has literally outgrown the pioneer museum it was planted behind.

A wild west cemetery in Tombstone, Arizona, provides a window into the Old West.

What is the Thing?

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

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

This giant steer-skull edifice refuses to die.

After a short-lived attempt to bring America in line with the rest of the world, this road was left in metric.

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

A reproduction of earth's many biomes.

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

The world's largest military aircraft cemetery.

This southwestern historic site was designed and built by an artist who wanted his work to "feel at home."

Miniature art that tells an enormous story.

A rare wayfinding portmanteau of “Street” and “Avenue.”

Sleep where gangsters fell amidst smoke and flame, with nary a bullethole to show for the legendary struggle.