This 19th century train workshop is a treasure trove of railroad history.

A replica of the first public theater built in California.

A massive volcanic plug is now a protected area that hosts a number of bird species.

A deserted hodgepodge of experimental structures designed by nearby university students.

A chain of bells connect the California Missions and honor the legend of the "King’s Highway."

Machinery left over from California's once thriving mercury industry now attracts artists and explorers.

Factory that once supported an entire company town of 350.

Coastal dunes, site of buried Egyptian movie set and former utopian colony.

Towering basalt columns, a creation of fire and ice.

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

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

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

Giant pinnacles in the sun-scorched lands of Southern Utah have been nicknamed "white ghosts."

A sharp bend in a dramatic river canyon cut through red rocks.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Legends surround this jagged rock formation in the New Mexico desert.

A well-preserved Ancestral Puebloan ruin tucked beneath a desert cliff.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

Millions of years of oxidation make a drive down this winding Death Valley road surprisingly colorful.

"Only the devil could play golf here."

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.

The location of the last stand of Charles Manson's doomsday cult.

This giant temperature attraction created some giant electric bills.

One of the oldest reform schools in the United States, home to wayward boys such as Merle Haggard, now abandoned.