The lush coastal city of Astoria is riddled with forgotten secret sidewalks.

A Roman-style column in Oregon hides a spiral staircase inside.

100-year-old shipwreck you can walk up to at low tide.

A tiny plaque hidden miles into the Washington wilderness is all that remains to honor a shipwreck that left 18 people dead.

A "Minnesota-style" pizza parlor in the Scandinavian heart of Seattle.

The remains of a former logging boom town, crumbled away in the forest.

A historic Masonic building overlooking the Puget Sound.

A glimpse into the "Logging Capital of the World" at a time when there was far more forest and far less machinery.

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

City Council meetings still happen in this historic building, impeccably preserved on the inside.

Remnants of a forgotten 1920s speakeasy and Prohibition-era murals were discovered in its basement.

The spur that wouldn’t die.

Protected from the elements, these Native American rock paintings have survived approximately 250 years.

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

A 1940s nuclear reactor built to produce plutonium for the Manhattan Project.

A frozen relic of Seattle's hydroelectric boom is now a teaching facility for future engineers.

In this subterranean brick arcade, a small shop continues the ancient practice of bookbinding.

The building features one of the last remaining free-floating spiral grand staircases in the U.S.

An annual celebration of the infamous, unsolved skyjacking.

This grove of ghostly cedars was killed in 1700 by an enormous tsunami, felt from the United States to Japan.

A comprehensive collection of bonsai set in a beautiful campus.

This large Sitka spruce that appears to be floating in mid-air, has defied logic for years.

This bridge provides safe passage for squirrels.

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