A volcanic tunnel illuminated by natural skylights offers a shaded respite from the desert sun.

The abandoned train depot now doubles as a well-placed rest stop for those who take the road less traveled.

Famously misunderstood wonder of the ancient world

The drama of nature in full effect in this Nevada State Park.

This former Mormon settlement is reemerging from the receding waters of Lake Mead.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

Preserving the remains of Native American cultures which otherwise would have been submerged behind Hoover Dam.

At this gas station in the middle of the desert, a convenience store has been carved directly into the rock.

Major tourist destination known for its bubbling mud-pools and hot thermal springs.

A galaxy of glowworms—larvae of a gnat—hides deep in the belly of these caves.

Tubing through a cave lit with glowworms is a magical underground experience.

Dyed by iron oxide over centuries, these sandstone rocks rise thousands of feet into the sky.

These otherworldly limestone formations jut out from the Kansas prairie.

This gallery of prehistoric red ochre art lines the wall of a scenic segment in Utah's San Rafael Swell.

Two tall rocks sit at the center of this site, once the home of a large Ancestral Puebloan community.

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

A unique blue and yellow phone booth in America's "Little Sweden."

When ecosystems collide in the arid Southwest.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

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

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

Curious rock formations in a tiny Kansas state park.

Holding multiple historical boats and an entire 19th century village, this New England attraction is the largest maritime museum in the world.

Public outcry led to this bridge's unique character which celebrates a giant frog battle and also sewing.