A Mars simulation in the southern Utah desert.

This rugged area of red rocks and arches is often considered one of the most beautiful places on Earth.

One man has installed bathtubs into the Utah desert floor to harness the powers of a natural hot spring.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

Once a menacing challenge for trailblazers, this trail is now the most scenic drive in Utah.

Despite its name, this route in southern Utah offers a heavenly day trip.

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

A classic Route 66 landmark that was built with scrap lumber and is held together with kitsch and puns.

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

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

An homage to everyone's favorite prehistoric cartoon family.

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

Dramatic river bend surrounds a natural red-rocked pedestal.

Rippling sand dunes frozen in the Arizona rock.

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

Taihape's claim to fame is a fictional Kiwi farmer wearing gumboots.

Ice roads, deep holes and 3,500 pounds of diamonds.

Hanging over one of Japan's "hidden valleys," these vine bridges must be remade every three years.

Inhospitable caverns just beneath this island paradise offer insights into alien worlds.

In paradise, feral pigs have claimed an island all to themselves.

A popular tourist cave with a dark past.

This naturally heated mountainous creek has created a group of neon blue pools of potentially deadly boiling water.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.