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

When ecosystems collide in the arid Southwest.

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

This "zoo" is a cross between a junkyard and a sculpture garden, featuring animals you won't see anywhere else.

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

The largest self-built castle in the U.S., six decades in the making.

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

This naturally-sourced hot spring is now home to a clothing-optional resort.

This modern antique shop is a museum for 1980's Saturday morning cartoon culture.

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

At one time this small mining village was the highest town in America but now it sits abandoned while the mine churns on.

An enthusiastically interactive mining museum that won't let black lung ruin the fun.

Abandoned silver mine strewn with wrecked and twisted structures.

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

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.