Here, at the "world's longest art gallery," you'll find forty miles of ancient petroglyphs and pictographs.

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

A miraculous natural phenomenon known as "the spring that breathes."

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

An architect's childhood fantasy treehouse made real.

A beautiful geyser under environmental threat.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

This rustic old building is said to be the most photographed barn in America.

This prison-turned-museum is a remnant of the Old West's grizzly, violent past.

A coal fire has been burning underground here since 1896.

A river runs through this remote valley in a very unexpected way.

A mental health hospital dating back more than 139 years, now features a museum.

The wreckage of a World War II bomber is hidden high in the Colorado wilderness.

When zealous marijuana enthusiasts kept stealing the "Mile 420" highway marker, the State of Colorado got creative.

Colorado's only true geyser is hidden within the San Juan National Forest.

The scene of one of the darkest moments in American labor history has been left essentially untouched since the tragedy.

At the tallest peak in Colorado, an electrifying mix of thin air, lightning, and rivalry.

Silver in the hills led to the speedy creation of this boom town and a lack of it saw the town abandoned nearly as quickly.

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

This spectacular track has run continuously since 1882.

Abandoned silver mine strewn with wrecked and twisted structures.

This Colorado hiking trail provides a small gold mine of abandoned gold mines.

Despite being one of the most photographed vistas in the Rockies these twin peaks are rightfully known as the "Deadly Bells."

The superstar of Cold War nuclear bunkers has been featured in countless films but is now barely operational.