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

Twin Peaks' real life Double R Diner has been restored to its damn fine television look.

The decorations were inspired by an unlikely missing treasure.

The Denny Substation has been called "the coolest substation in the world" and sits in a densely populated Seattle neighborhood.

The longest and widest floating bridge in the world.

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

A giant roadside black bird marks the location of this eclectic local mall.

A giant milk bottle from the 1930s beckons drivers to this diner.

The four tall pillars once marked the entrance of the historic Seattle church that fought for women's suffrage and civil rights.

This metallic stampede sits frozen on a Washington ridge yet the artist's vision is still incomplete.

This inanimate goat created by the "welding nun" has been helping to clean up the city of Spokane for more than 40 years.

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

This famous bridge twisted itself into oblivion, but not for the reason you might think.

Allowing humans and fish alike to migrate from freshwater to saltwater and back again.

This grand old 80-foot sequoia towers above the buildings in the city’s retail center.

Site of the greatest known waterfall that ever existed.

A bike being "eaten" by a tree is the real Vashon legend behind popular children's book, "Red Ranger Came Calling."

One small town in the Pacific Northwest transformed itself into a Bavarian-themed tourist destination.

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

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

The tech giant built three enormous glass orbs in Seattle so employees could work inside a rainforest greenhouse.

Though strikingly beautiful, Seattle's other railway station is now largely forgotten.

An obscure waterfall that looks like something out of a fantasy novel.

This former coal gasification plant found a curious second life as a popular public park.