The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

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

In a 345-million-year-old cave that's 200 feet underground, dinner awaits.

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

A self-built castle made by a mysterious man.

The biggest pinball arcade in the world has over 600 pinball machines, and 300 arcade machines.

The flow from this waterfall sometimes comes out of springs below its rim.

This small shack near the entrance to Sequoia National Park has been in almost continuous operation for the last century.

This hiking/biking/horse trail along an old railroad grade features trestles, tunnels, and a roadless stretch through the scenic Susan River canyon.

In one of the hottest parts of the Mojave Desert, shallow bedrock forces the typically dry Mojave River to the surface in this canyon, providing a vital oasis for humans and wildlife.

The disdain for this dysfunctional dam is reflected in a giant pair of scissors painted on the concrete face.

Outside San Francisco lies a small clown cemetery and memorial.

A shockingly detailed small scale recreation of the temples of Abu Simbel.

The echoes of a railroad town that solemnly mark the end of the line.

This 19th-century museum inside of a lighthouse is only accessible during low tide.

Where a railroad loops under or over itself to rise or drop more than 70 feet in a short distance.

Each summer, the migratory bats living beneath the bypass form "batnadoes" at dusk.

Catch a glimpse of the elusive Peninsular bighorns right off of the desert freeway.

The famous blue house from the classic horror film "Halloween" is now a local landmark.

This hidden amusement park is a magical escape for kids and kids-at-heart.

Instead of faces, these sculptures have barcodes—statements on societal dehumanization.

Across Ring Mountain is a vast collection of Native American petroglyphs unique to the region.

This hidden fire lookout offers spectacular views of Sequoia National Park.

A 19th-century cabin built into a hollowed-out Sequoia tree.