One of the world's largest telescopes, stares into the night sky with two huge mirrors.

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

An artificial crater field that trained astronauts for lunar exploration.

Don't blink or you'll miss it.

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

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

All of the 20 occupied houses in this mostly abandoned town feature some curious display of junk art.

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.

Limestone caves with spectacular showcase chambers.

The story of Two Guns, Arizona could easily be described as a Shakespearian tragedy on Route 66.

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.

The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

One of the largest, oldest, darkest, quietest motel rooms in the world.

A stealthy Apache hideaway that became the haunting site of a mass grave.

An homage to everyone's favorite prehistoric cartoon family.

An arsenic-filled pool in the Grand Canyon takes on the appearance of a giant, overflowing pumpkin.

In a 345-million-year-old cave that's 200 feet underground, dinner awaits.

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

A self-built castle made by a mysterious man.

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

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

Dramatic river bend surrounds a natural red-rocked pedestal.