Sasqu(w)atch out!

A plaque commemorates the spot in the Oregon woods where the first-ever Geocache was hidden.

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

This lake in the Cascades lives up to its name, disappearing down a hole every spring.

Hollowed out cedar log tubs set in an ancient towering forest.

The seamy, underground secrets of Portland's criminal past.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

Once the fastest ship from San Francisco to Tahiti, the Galilee now lays in pieces in three different cities.

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

The only visible piece of San Francisco's most famous shipwreck.

Over 315,000 preserved amphibians and reptiles in jars.

The randomness of this wall of lava lamps helps encrypt up to 10 percent of the internet.

San Franciscans leave gifts and messages for the magical beings that live behind the tiny, mysterious door installed on a tree in Golden Gate Park.

Nuclear waste dump site now an environmental sanctuary.

The stones that traveled from Spain to eventually become a holy place for San Francisco's nature worshippers.

This partially buried wreck is one of the most complete of its kind but is only revealed when the sea allows.

Gold Rush-era tombstones line the park's paths.

An overlooked and unassuming engineering marvel.

A 300-ship graveyard, with a few still visible at low tide.

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

Visible below the waves are memorials to the city's Gold Rush dead.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.