A well-preserved example from a 1920s network of airmail navigation arrows sits near Interstate 15 in southern Nevada.

Along the Outback Scenic Byway, adjacent to hot springs, this human-made geothermal feature takes unexplained breaks.

A well-preserved set of ruins not far from Lovelock.

How a bat poo mine became a major Native American archaeological site—and connections to legendary red-haired giants.

Once a menacing challenge for trailblazers, this trail is now the most scenic drive in Utah.

An incredible airplane graveyard sits outside this small museum dedicated to preserving aviation history.

This remote desert watering hole has a connection to a curious chapter of American history.

A small canyon with petroglyphs and a seasonal waterfall, only a short hike from the remnants of old Route 66.

Eons ago, a rushing lava river formed this pristine passage through solid rock.

An artificial crater field that trained astronauts for lunar exploration.

This historic national park is covered in the stunning ruins of red rock pueblos.

The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

A stealthy Apache hideaway that became the haunting site of a mass grave.

An off-the-beaten path cave with an underground lake.

This 40-room dwelling tucked within a cliff was built by the basin's prehistoric residents.

A partial tunnel blasted into a steep ridge is all that remains of a failed railway across Arizona.

Once a year, at exactly 11:11 a.m., this monument comes to life.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

This fireplace-turned-monument pays tribute to the assassinated U.S. president.

Hike the unusual hoodoos and rock formations that form this little-known natural wonder.

The remote resting place of a notorious Wild West outlaw whose death is shrouded in mystery.

The former home of the army detachment that captured Geronimo.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."