Beehive charcoal kilns and slag deposits mark this late 19th century camp centered on a smelter.

An iron monument on the 120th meridian as surveyed, one of only four marking the boundary between Nevada and California north of Lake Tahoe.

A Native American petroglyph, the site of an emigrants' waystation, and the ruins of an early 20th-century sheep camp are all found at this crossroads.

Once owned by the largest employer in Colorado, these ovens have been abandoned for over a century.

A stretch of highway even lonelier than the so-called "Loneliest Road in America."

This extraordinary model train layout covers over 1,700 square feet, with multiple trains running simultaneously.

A comprehensive collection of toy and model trains, largely from the mid-20th century.

A field of nothing but boulders which resembles a giant's gravel driveway.

This eerily well-preserved coal town was saved from destruction by a Sean Connery movie.

Metal monsters made from repurposed materials lurk alongside this Pennsylvania road.

This jail which was in service for over a century is now open for curious visitors.

The "Grand Canyon of Southwestern Idaho" makes a spectacular gash across the flat Snake River plain.

Beneath the southern end of the Golden Gate Bridge is the “Gibraltar of the West Coast,” a fort built to protect the San Francisco Bay from naval attack.

The second-largest giant sequoia in the world.

A haven for wildlife amid the farmlands and development of the Willamette River Valley.

Named for a prominent scout and explorer, this Wyoming state park encompasses a replica of an 1840s trading post, a 19th-century Army outpost, and early 20th-century automobile lodgings.

A large wind turbine installation in central Washington State is home to an extensive set of interpretive exhibits.

This lighthouse has been guiding shipping into the Golden Gate since before the American Civil War.

This open-air reconstruction of an Old West town, a cross between a theme park and a museum, provides an immersive historical experience.

A late-19th century diversion canal built by hand crosses Bryce Canyon National Park and is still in use.

A remarkably well-preserved stage stop from the late 19th century in a remote part of Nevada.

The only bridge in the United States where BASE jumping is legal without a permit year-round.

A mine in the Sierra Nevada that produced nothing but barren quartz.

A well-preserved sheepherding camp now lies in the heart of the Granite Chief Wilderness, in the high Sierra Nevada.