At the time of its completion, it was the tallest dam in the world.

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

Originally conceived as part of a proposed Arizona State Capitol building in the 1950s, this structure built in 2004 stands as a monument to the architect's legacy.

Once disputed as the largest sundial in the world.

The stone circle honors the 19 firemen who perished during the Yarnell Hill Fire.

The longest living non-clonal organisms on Earth.

A gothic palace of endless stalagmites and pseudoscorpions waits within one of the world's most beautiful caves.

This Stonehenge-inspired solar calendar stands alongside a landfill, in the middle of the Nevada desert.

The drama of nature in full effect in this Nevada State Park.

The notorious Wild West outlaw was raised in this unassuming abode.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

A tunnel with windows, so you don't miss out on the impressive views.

The unusual patterns in this rock formation result from two distinct modes of weathering.

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

These elusive, isolated rodents evolved into a distinct, locally iconic subspecies.

Rippling sand dunes frozen in the Arizona rock.

The eroded core of an ancient volcano is now accessible by a short hike.

A wild west cemetery in Tombstone, Arizona, provides a window into the Old West.

Walk through the actual strap iron cells and solitary chambers of Arizona Territory’s first prison.

An old saloon in the West filled with history, and according to some, a few dozen ghosts.

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.

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

A spiritual vortex among the red rocks in Sedona.