One of the world’s largest collections of petroglyphs records 2,000 years of human activity.

The fifth-longest natural arch in the world, and the longest outside China.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

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

New fungal and bacterial species call this deadly lake home.

A collection of huge Pre-Colombian structures in Alabama.

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

When an ancient supervolcano erupted, some of Nebraska's prehistoric animals were forever preserved in ash.

This erect, phallic geological spire wasn't always named so domestically.

An experimental, automotive replica of Stonehenge.

This public square capitalized on a single Eagles reference to bring some life back to an Arizona town.

Open since 1938, this diner has kept its fountain, malt machine, and all the gum that greasers left beneath its counter.

A museum and tribute to a brave profession.

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

One of the oldest Mexican restaurants in the United States air-dries its trademark beef in a dangling outdoor cage.

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

In Tucson a giant metal snake helps pedestrians cross a busy highway.

An Arizona museum with a collection of pharmaceutical oddities, including a jar of a gangster's chewed gum.

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

The world's largest military aircraft cemetery.

Legend says train robbers stashed their gold within the depths of this unusual cave.

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.

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