In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A 140-year-old castle with underground caves hidden in San Francisco.

A psychedelic labyrinth on the San Francisco bay.

Shoreline strewn with the remains of ghostly fallen trees.

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.

A Boeing mechanic and his wife leave a whimsical, stone sculptured garden as their legacy.

An electrifying collection of gadgets and literature from the 16th through 20th centuries.

The cardinal directions, set in stone.

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

A collection of odd-shaped and quirky sounding instruments handmade by a midcentury inventor-composer.

This monument remembers the first Japanese Americans forcibly relocated during World War II.

Quirky movable sculptures have been racing through the town since 1983.

This sci-fi gazebo located in a Washington power town is made from old bits of industrial electrical equipment.

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

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

An enclosed rotunda at the Henry Art Gallery in which viewers can look up and see the uninterrupted sky.

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.

"Enter and be entertained or annoyed by Dada in Walla Walla."

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

The site of the Wellington avalanche, one of the America's worst railroad disasters.

Activists are fighting to preserve these unfinished highway ramps as a tribute to the citizen revolt that halted their construction decades ago.

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

This bridge provides safe passage for squirrels.