Twice a year, visitors can tour the desolate site that birthed the Atomic Age.

This is one really big nut.

Legends surround this jagged rock formation in the New Mexico desert.

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

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

A museum dedicated to the alleged Roswell Incident.

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

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

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

The land is full of geologic eye candy, such as otherworldly spires, mushroom-shaped hoodoos, and prehistoric fossils.

You can stand in three U.S. states at once.

You might want to bring a rain jacket to this travertine triple waterfall.

Once owned by the largest employer in Colorado, these ovens have been abandoned for over a century.

A multicolored mineral mound dribbles piping hot spring water right off the side of a highway.

The remains of a World War II-era Japanese American internment camp dot a windswept Colorado hill.

A dangerous narrow-gauge railroad once traced a route through this striking canyon.

This marker identifies the location where three states converge.

Take a dip in the world's largest mineral hot springs pool.

Even in death, he's still your huckleberry.

This super steep hike ascends 2,000 feet in less than a mile.

The highest paved road in North America winds its way up Mount Blue Sky in Colorado to an altitude of 14,130 feet above sea level.

These faux-cliff dwellings allow visitors to climb around on a replica archaeological site.

This spectacular track has run continuously since 1882.

When ecosystems collide in the arid Southwest.