This once-popular otherworldly landscape was formed by one of the largest volcanic eruptions in history.

Historic, 19th-century wagon wheel ruts cut into soft volcanic ash.

A mural of the Virgin of Guadalupe painted on the rock wall by canyon's religious namesake.

When ecosystems collide in the arid Southwest.

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

A coal fire has been burning underground here since 1896.

A long and winding trail through history led to the current iteration of this mountaintop tower.

Even in death, he's still your huckleberry.

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

This three-mile concrete levee in Pueblo, Colorado was transformed into the world’s longest painting.

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

An abandoned sawmill from more than 134 years ago stands testament to the ambition of one man.

All that remains of this once-booming mining town are the ruins of a saloon.

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.

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

The site of the "Bone Wars" between two rival paleontologists during the dinosaur rush of the 19th century.

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

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

One of the smallest towns in the United States.

Miraculous tree that seems to sprout out of solid rock.

The narrow mountain road that carves a path between Florence and Victor is tied to ghost towns and ghost stories.

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

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

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