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

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

Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

This remote Colorado canyon is home to the second-largest collection of natural arches in the world.

The remnants of the base where US Army troops learned how to fight in extreme conditions.

When ecosystems collide in the arid Southwest.

A short but powerful waterfall resides amid Colorado’s Great Sand Dunes.

This shrine is an ode to the region's rich Hispanic heritage.

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

Once a dining hall for boarding school students, this lodge was a popular haunt for nuclear physicists working on the Manhattan Project.

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

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

Thousands of pieces of art have been carved into the rock at the site of an ancient volcanic eruption.

These unique volcanic rock formations offer the perfect opportunity to camp and hike.

Hidden in the Chihuahuan Desert resides an amazing collection of petroglyphs.

Explore a misty river canyon from a metal bridge system.

These ruins of a pre-Columbian cliff village are among the most beautiful and well preserved in New Mexico.

High in the Sacramento Mountains, a facility dedicated to studying the sun.

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

More than 21,000 images fill this overlooked gem of a prehistoric site.

This volcano rises like a giant anthill from the plains below, with a road spiraling up to the rim.

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

The largest dinosaur trackway in North America is tucked away among this canyon's ghosts and archaeological gems.

This massive home was constructed by one of the greatest conservationists in Colorado history.