This frozen tunnel in central Alaska is both an engineering feat and a valuable climate classroom.

Gorgeous cave resemble a winter wonderland.

The ghostly remains of what was once the world's richest copper mine.

Colorful boxes placed over the dead are left to rot and crumble.

Mind-blowing carvings and fantasy ice scenes grace the largest year-round ice environment in the world.

The Magical World of George Phar Legler.

This hidden gem in Arizona is truly worth the rugged journey.

This iconic 1958 tower welcomes air travelers to Tucson with neon-lit letters and architectural style.

An important piece of history from mankind's journey to the moon sits in the lobby of a government science lab.

This isolated outpost was once the only place to cross the Colorado River for hundreds of miles.

The largest copper mine in Arizona, this enormous open pit emerges from the hills like an alien landscape.

This remote desert watering hole has a connection to a curious chapter of American history.

One of the most extensive and well-preserved collections of dinosaur footprints in North America.

A Wild West jailhouse that slid down the mountainside.

For those going through a life transition, a place to leave behind a piece of your former self.

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

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

Limestone caves with spectacular showcase chambers.

Witnessing the might of this dessert-colored desert waterfall is a rare, powerful treat.

Ancestral Puebloan ruins, natural arches, and box canyons abound in this seldom-visited corner of Monument Valley Navajo Tribal Park.

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

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

Rippling sand dunes frozen in the Arizona rock.

This old army installation has worn many hats throughout its history.