A mental health hospital dating back more than 139 years, now features a museum.

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

A futuristic hovertrain is parked unceremoniously alongside a nondescript road.

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

This memorial pays homage to Pueblo's four Medal of Honor recipients.

Check out a hidden collection of vintage neon signs.

This historic stone barn is the former home of legendary cattleman Charles “Lonesome Dove” Goodnight.

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

Once a lonely sentinel on the edge of the Great Plains, this rebuilt trading fort offers a glimpse of life on the Santa Fe Trail.

A tiny nondenominational church harkens back to the days of the first homesteaders in the region.

Inside this shop, visitors are treated to a unique blend of natural history and art.

This Boeing KC-97 tanker is now a restaurant for aviation lovers.

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

The remains of the dam that unleashed a 15-foot wall of water on Denver.

Visitors can walk over the largest concentration of Columbian mammoths to have died from one event.

This underwater old Texas hill town only resurfaces during harsh drought.

Hike the ruins of a zoo that was shut down by an unsolved murder.

This soda factory is one of the last in America to use real cane sugar despite the protestations of Dr Pepper.

Tracks near this Texas nature site were once thought to support the Creationist belief that man and dino coexisted.

This abandoned building made of petrified wood was once a hotspot for buying moonshine.

Two massive and unstable sinkholes are yearning to unite, and their consummation could be catastrophic.

A mysteriously abandoned campsite in San Angelo State Park.

A popular swimming hole that hides one of America's most deadly diving spots.

One of the final grand railway depot hotel complexes is slowly being restored to its former glory.