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

The haunted reputation of these abandoned Colorado train tunnels is probably not helped by the terrifying spiked fence.

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

A little-known hot spring haven right below the highway.

The world's largest carnivore sanctuary is home to over 450 meat-eating rescues.

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

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.

The highest bridge in America was built for an almost unnervingly small amount of money.

At this Denver landmark, the meals are compulsory, the sopapillas are complimentary, and the insanity is everywhere.

Hidden beneath a bridge, this waterfall is known for the large amounts of graffiti painted on its base.

A technicolor place of worship for Elevationists.

A breathtaking array of ancient Pueblo structures and artifacts counterintuitively preserved by neglect.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Paranormal experiences in this hotel's room 217 led Stephen King to write "The Shining."

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

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

This unusual lava tube spouts seawater during high surf.

A cooled lava flow from the Haleakalā volcano formed these surreal-looking columnar basalt structures.

Once home to over 8,000 exiled Hawaiians suffering from Hansen's Disease.

A Hawaiian stairway to heaven—that you can't climb.

More than 2,000 species of tropical plants call this nature preserve and sanctuary home.

A unique set of caves that spits waves back out into the ocean.