This spectacular bridge supported by two gigantic hands looks like something out of a fantasy universe.

Once the largest town in eastern Yuba County now sits abandoned.

Hidden inside a gift shop that doubles as a museum, this gargantuan yo-yo can only be operated by crane.

Sasqu(w)atch out!

This natural marble cave is one of only five national monuments in Oregon.

This abandoned motel doesn't welcome guests anymore, but decay and a creepy atmosphere still call it home.

Each winter this underground cave forms a dazzling ice palace.

This strange hill on Old Fort Road where gravity works in reverse has been fascinating locals for years.

The drama of nature in full effect in this Nevada State Park.

A gothic palace of endless stalagmites and pseudoscorpions waits within one of the world's most beautiful caves.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

Located in the remote Monitor Valley, this travertine bowl contains a scalding pool of water.

This famous Nevada gold mine, once a hotbed of Wild West shenanigans, is now open for tours.

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

This sun-scorched lakebed contains samples of half the natural elements known to humankind.

The remains of the first public diamond mine in Arkansas.

An internationally-recognized dark sky sanctuary lies in northern Nevada, near the Oregon line.

Mine your own precious stones.

A poignant memorial to a young boy whose death spurred a dramatic increase in organ donations in Italy—dubbed the "Nicholas Effect."

This abandoned boat was left in place thanks to its rotting beauty.

A working model of the entire San Francisco Bay and much of the Sacramento River Delta, complete with regular tides that change every 14 minutes.

Forgotten and then destroyed by fire, this was once one of the largest saltwater swimming pools in the world.

Tenacious mummies survived dental problems, eternal entombment, and more than their fair share of devastating fires.

A promotional sun clock on the site of San Francisco's great raceway.