The decaying ruins of a failed mining company’s water diversion project cling to the side of a desert canyon.

It's safe—and permitted—to walk across these twin natural sandstone arches.

This balancing rock is one of Utah's most unusual geological formations.

A glimpse of a waterfall is reached by a steel catwalk along a slot canyon located in an Ouray city park.

Two creeks flow out of either end of this canyon in opposite directions.

A dangerous narrow-gauge railroad once traced a route through this striking canyon.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

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

A ghost town that held steady longer than most, but finally gave up the ghost.

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

This razorback ridgeline has doubled as a scenic drive since the early 1900s.

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

Running under an entire mountain, the longest highway tunnel in North America is kept fresh using portal fans and jet fans.

This small city where almost everyone lives in the same building can only be reached via North America's longest tunnel.

This WWII-era military installation once held an entire city within its walls - now, its walls are falling down.

An Alaska livestock farm devotes itself to harvesting wool from creatures that once ran with mammoths and sabertooth tigers.

Four-story concrete hotel never opened to customers.

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

The moving metal works of one troubled artist can still be viewed on his front lawn... for now.

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

The king of U.S. high points towers over every other peak on the continent.

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

The highest paved road in North America winds its way up Mount Blue Sky in Colorado to an altitude of 14,130 feet above sea level.

A museum dedicated to the history and exploration of both popular music and science fiction.