An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

A museum dedicated to the alleged Roswell Incident.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

Dozens of elaborate works of automotive art have been preserved at this Arizona museum.

This Old West hotel, the longest in continuous operation in the state of Arizona, is claimed to be haunted.

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

Stairs often replace streets on the steep slopes of this old mining town.

After a short-lived attempt to bring America in line with the rest of the world, this road was left in metric.

Red sandstone structures dominate this landscape, which has been inhabited for some 5,000 years.

The biggest solar telescope in the world helps reveal the secrets of our sun.

A living snapshot of a different time in America is preserved and maintained by a community of volunteers.

A reproduction of earth's many biomes.

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

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

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

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

Hikers and walkers flock to this historic volcanic butte for its scenic desert views.

Enormous photography collection housed in a study center co-founded by Ansel Adams.

A colony of Mexican free-tailed bats live under the bridge and take flight at sundown all summer long.

Previously a hot spring, this park remains a site of unique history, wildlife, and geology.

A rare wayfinding portmanteau of “Street” and “Avenue.”

This church on a Tohono O'Odham reservation has stood since 1797.