A geological mystery on Camelback Mountain.

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

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.

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

The scene of one of the darkest moments in American labor history has been left essentially untouched since the tragedy.

When ecosystems collide in the arid Southwest.

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

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

This grand stone tower was dedicated to a famed American humorist almost by coincidence.

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

There are eight natural springs around town, each with a slightly different taste.

While most of the games in this arcade take quarters, that would have been a small fortune when they were made.

Thanks to a quirk of elevation this gift shop produces magic doughnuts that are found nowhere else on Earth.

Air Force Academy Chapel made of 100 identical tetrahedrons works to inspire those of all religions.

The largest source of fossilized insects anywhere.

A small horde of mythical creatures lurk almost imperceptibly within the museum's wildlife dioramas.

One Confederate statue that accurately reflects the ugliness of its subject.

This replica of the Greek structure is in the heart of Nashville.