A monument to the frontier doctor who came up with the idea of delineating highways with a painted line.

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

Along a California highway is a kind of Jurassic Park made of metal.

In the middle of an extremely unforgiving and desolate high desert is the most secret military facility in the world.

An abandoned Jazz Age dream home and con man's hideout in Death Valley.

An errant donkey ushered in a new era of mining in Nevada.

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

What is the Thing?

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

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

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

An eatery for UFO seekers on the Extraterrestrial Highway.

Mysterious meeting place for UFO hunters near Area 51.

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

A haunted hot springs hotel that went from healing retreat to asylum before it was restored.

Oldest building in California still in use.

The world's largest wooden trestle stretches across this desert canyon in Anza-Borrego Desert State Park.

Where there's quartz, there must be gold. Thus is the story of the mines of Julian, and the titillating times of the Gold Rush.

A hand-built folk art installation covered with messages of God's love.

This abandoned Navy base was transformed into an off-grid alternative living community for thousands of people.

The ghostly remains of an accidental sea.

A monument to a one-legged kidnapper, horse thief, and charlatan asks visitors to throw rocks in a pile.

This simple highway curve has become a comedic pilgrimage site.

Bananas are often left for the first monkey America ever recovered alive after being launched into space.