A nature and cultural preserve named for its multitude of petroglyphs carved by the Northern Sinagua people.

A pair of giant roadside arrows are all that remains of a former Route 66 trading post.

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

This giant steer-skull edifice refuses to die.

The fading, forgotten remains of a once bright and booming factory.

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

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

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

A once popular resort—said to be the vacation spot of gangster Al Capone—now remains abandoned in the woods of Arizona.

An urban laboratory.

This 40-room dwelling tucked within a cliff was built by the basin's prehistoric residents.

An abandoned facility that has become a place of ritualistic satanic worship, or so rumor has it.

This collection of Wild West movie memorabilia also claims to hold some secrets of the Lost Dutchman's mine.

These free-roaming horses were once destined to disappear from the land.

A self-built castle made by a mysterious man.

A mysterious "wedding cake" castle in the middle of the urban desert.

Thousands of Mexican Free-Tailed Bats soar around an abandoned storm drain at sunset each summer.

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

Open since 1938, this diner has kept its fountain, malt machine, and all the gum that greasers left beneath its counter.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

The historic “pink house on the hill” is an architectural gem that now serves as a center for water conservation.