Native American burial mounds? Giant gopher dens? No one knows what created the Mima Mounds.

Essence of hound's tongue and tincture of bloodroot are just the tip of the herbalist iceberg at this beautiful, impressively-stocked apothecary.

An abandoned 19th-century hospital now swirling in ghost stories.

This former mining hub holds a surprising abundance of undisturbed relics from the Old West.

One of the largest cat sanctuaries in North America is considered a "Club Med" for felines.

A cave interior in the shape of the ancient rhinoceros, created by lava cooling around its carcass.

Site of the greatest known waterfall that ever existed.

This remarkable collection devoted to the study of fish includes 1 million preserved specimens from all around the world.

The second tallest railway trestle bridge in America.

People come from across the globe to swim in this lake believed to have healing properties.

An American city stranded at the tip of a Canadian peninsula where strict adherence to the "49th parallel rule" became problematic.

This dilapidated ship carcass covered in trees is a striking sight.

Four abandoned towers hidden above the Douglas fir forest in Washington.

A nearly abandoned 19th-century town on the Palouse.

The small town of Poulsbo in Washington state is the next best thing to the Kingdom of Norway.

"The Reptile Man's" very own roadside zoo features an albino alligator.

A surreal landscape where fanged rocks rise from the ground and the ocean feels like a great mystery.

Former farm staffed by mental patients is now a public park.

Hundreds of hopeful gold miners came here to get rich, but only two years later the small town was deserted.

The highest point in Washington state is a volcano covered in glaciers.

This long, dark tunnel is open to hikers, but those without lights are known to get confused even on the straight path.

Shoreline strewn with the remains of ghostly fallen trees.

"The House That Love Built" is shying away from "The House That Ghosts Love."

A beautiful final resting place for some of the noteworthy deceased.