An ancient system of freshwater caves filled with animal bones, including that of species long-extinct.

Few of the many visitors to this resort town know of its hidden Maya ruins.

One of Mexico's least-visited archaeological sites is tucked away inside a theme park.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

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

These aggressively sustainable art homes look like something out of 1970's science fiction.

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

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.

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

This nearly abandoned town was once a thriving mining community until a series of fires.

The world's only teal arches exist in a city that cares more about its aesthetic than an Instagram influencer.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

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

In the middle of a busy airport, a statue honoring the astronaut who told Houston that Apollo 13 had a problem.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

One of the greatest heroes of the Titanic tragedy came from humble beginnings to this beautiful home.

This museum offers an actual time machine back through Colorado's past.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

A Rocky Mountain city provides a happy ending for a pinto pony and his Brobdingnagian red chair.

Overlooking the Colorado Convention Center is this giant sculpture made from thousands of triangles.

A multiversal transit station located right below a highway interchange.

One of the oldest continuously operating amusement parks in the U.S. is an open-air museum of Art Deco and neon lights.

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