When ecosystems collide in the arid Southwest.

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

Two tall rocks sit at the center of this site, once the home of a large Ancestral Puebloan community.

No one knows exactly how deep the world’s deepest geothermal hot spring is.

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

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

This quirky hot springs town known to locals as "T or C" was named after a radio show.

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

A museum dedicated to the alleged Roswell Incident.

This fast-food outlet is the only space and UFO-themed McDonalds in the world.

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

The only thing still moving in this town is the eponymous hot spring.

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

This railroad magnate's 19th century tower is more than a little bit out of place in the Nevada desert.

Only intact Ichthyosaur skeleton in the United States and an abandoned gold mine and ghost town all in one place!

These huge stone ovens in the desert fueled the Nevada silver boom, and may have also been a hideout for outlaws.

This Old West eatery along America's Loneliest Road was originally a stop on the Pony Express.

A tree bears footwear on the loneliest road in America.

This massive solar generating facility in the Nevada desert has been plagued by difficulties.

In the middle of a remote desert town is a surprisingly opulent hotel.

In the middle of an extremely unforgiving and desolate high desert is the most secret military facility in the world.

A sharp bend in a dramatic river canyon cut through red rocks.

An eatery for UFO seekers on the Extraterrestrial Highway.

A remarkably well-preserved brick chimney from a smelter dating to the 1860s is all that remains of this former mill.