A multi-storied adobe complex has been inhabited for more than a thousand years.

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

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

A museum dedicated to the alleged Roswell Incident.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

A Wild West jailhouse that slid down the mountainside.

On the outskirts of a reborn ghost town, a decaying post office remembers the bad old days.

A stealthy Apache hideaway that became the haunting site of a mass grave.

Dramatic river bend surrounds a natural red-rocked pedestal.

Rippling sand dunes frozen in the Arizona rock.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

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

Home to Hollywood history and a very special salt crystal.

Once an ambitious nature spa, these forest ruins now provide a serene monument to failure.

The show pony of cave systems, Fantastic Caverns manages to live up to its name.

The ravine where Jesse James supposedly performed an impossible jump to evade capture.