The only diamond mine in the world where you can keep what you find.

Millions of years of erosion created the feature for which this rock formation is aptly named.

A planet-hunting astrograph built in the 1920s to seek out the so-called "Planet X" beyond Uranus.

The world's only teal arches exist in a city that cares more about its aesthetic than an Instagram influencer.

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

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

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

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

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

A propulsion engine testbed that paved the way for the Space Shuttle launch sits without recognition at this rocket center.

It may look like no more than a full-scale model, but every part of this full Space Shuttle stack had a working role in aviation history.