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

Every year, festive decorations appear on this juniper tree located in the median strip of a busy highway.

The final resting place of the businessman-turned-astronomer who helped discover Pluto stands near his observatory.

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

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

The first permanent memorial to a unique secret weapon of World War II.

A geological mystery on Camelback Mountain.

This public square capitalized on a single Eagles reference to bring some life back to an Arizona town.

This immigrant bridge once spanned the Thames but is now a fixture of an Arizona city.

This giant steer-skull edifice refuses to die.

A Wild West jailhouse that slid down the mountainside.

An urban laboratory.

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

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

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

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