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

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

A phenomenal assembly of pueblos in New Mexico is the most complete example of ancient ruins north of the border.

Belly up to the bar in Cowtown, don't forget to buy some boots.

The United States's largest hand-dug well is topped with a state-of-the-art museum.

Officially named the "Loneliest Road in America," this barren stretch of Nevada road offers almost nothing but sky and open fields.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

Permanent exhibit reminds visitors of the Exxon Valdez.

An auroral research program that superheats the ionosphere.

The king of U.S. high points towers over every other peak on the continent.

North America's first frozen mummified remains of an ice age steppe bison, the 36,000 year-old mummy named "Blue Babe."

A trading post in the North Pole where children send letters.

The official atomic museum of the United States explores the explosive and productive history of a much maligned energy source.

Deadly airliner crash preserved for those willing to climb and pay respects.

A unique geological area spiked with wind-carved rocks that resemble teepees.

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

This museum started as a collection of Manhattan Projects and continues to add exhibits as they are declassified.

Despite time, colonization, and the brutal New Mexican heat, these Pueblo ruins still stand.

The ruins of this abandoned fort now stand as a picturesque reminder of America's march West.

A clear blue swimming hole with hidden caves, still unexplored.

The site of Billy the Kid’s most famous escape and the end to the Lincoln County War.

A small flooded ghost town with a few scattered structures remaining.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

A Mars simulation in the southern Utah desert.