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

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

A self-built castle made by a mysterious man.

Open since 1938, this diner has kept its fountain, malt machine, and all the gum that greasers left beneath its counter.

A geological mystery on Camelback Mountain.

One of the largest, oldest, darkest, quietest motel rooms in the world.

These free-roaming horses were once destined to disappear from the land.

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

See massive fossils that are over 200 million years old in northeastern Arizona.

A monument to the one-armed geologist who led the first documented expeditions through the Grand Canyon.

A motel dedicated to Southwestern nostalgia.

The remnants of a creative early method of wildfire prevention.

A working cattle ranch with remarkably well-preserved prehistoric petroglyphs and ancient ruins.

Along the old Route 66 is an abandoned trading post made from old telephone poles, built by a former circus clown.

An homage to everyone's favorite prehistoric cartoon family.

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

The largest natural travertine bridge in the world is nestled in a small canyon in central Arizona.

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

A once popular resort—said to be the vacation spot of gangster Al Capone—now remains abandoned in the woods of Arizona.

Witnessing the might of this dessert-colored desert waterfall is a rare, powerful treat.

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

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

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

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