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

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

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

Limestone caves with spectacular showcase chambers.

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

A spiritual vortex among the red rocks in Sedona.

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

The Magical World of George Phar Legler.

An homage to everyone's favorite prehistoric cartoon family.

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

A reproduction of earth's many biomes.

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.

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

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

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

Most-visited and most-photographed slot canyon in the American Southwest.

Rippling sand dunes frozen in the Arizona rock.

The sculpture's largest spire points directly toward the North Star.

A high school astronomy enthusiast designed this model of our solar system to be traversed on foot.

This shrine to the patron saint of Alaska sits on a small tidal island and was built from the land’s own beach stones.

This historic collection of Native Alaskan artifacts was resurrected through a partnership between the WPA and tribal artisans.

An abandoned aircraft sits submerged in a lake in the Alaska wilderness.

This WWII-era military installation once held an entire city within its walls - now, its walls are falling down.