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

After a short-lived attempt to bring America in line with the rest of the world, this road was left in metric.

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

The world's largest military aircraft cemetery.

One of the largest open-pit copper mining operations in the entire country.

A rare wayfinding portmanteau of “Street” and “Avenue.”

The biggest solar telescope in the world helps reveal the secrets of our sun.

A cabinet of curious mathematical models and old calculators.

Sleep where gangsters fell amidst smoke and flame, with nary a bullethole to show for the legendary struggle.

Miniature art that tells an enormous story.

An Arizona museum with a collection of pharmaceutical oddities, including a jar of a gangster's chewed gum.

In Tucson a giant metal snake helps pedestrians cross a busy highway.

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

A natural history wunderkammer in the middle of the desert.

The Magical World of George Phar Legler.

This southwestern historic site was designed and built by an artist who wanted his work to "feel at home."

Opinions differ as to whether this Arizona tree was actually used as a Wild West jail, but that hasn't stopped the town from capitalizing on it.

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

Take a monster truck tour around an ostrich farm in the middle of the desert.

Concrete crosses scattered across the Arizona scrubland which were used to align spy satellites.

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

This abandoned horse racing track was an exercise in hubris from its inception.

A towering bronze statue memorializes the founding father of postwar American conservatism.

This striking public art installation is suspended above a public park, designed to gently move in the breeze.