Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

An outdoor sculpture park of giant pink robots and post-apocalyptic Christmas scenes.

A tiny red pebble marks what may be the quietest outdoor spot in the United States.

An essential stop before plundering, BYO Cutlass.

This Big Sur waterfall drops 80 feet directly into the Pacific Ocean, and inspired the hillside house up top.

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

An extraordinary mixture of natural beauty and man-made phenomena.

This Los Angeles animation studio is keeping the wonder of stop motion puppetry alive.

A clear blue swimming hole with hidden caves, still unexplored.

This charmingly homemade amusement park has been growing for 40 years.

Couple's personal collection of pinball machines turned public pinball museum.

A little piece of the Shire is hidden behind a plant nursery in Port Orchard, Washington.

A house filled to the brim with oddities and curiosities.

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

The longest continuous lava tube in the continental U.S. offers 2.5 miles of dark explorations for the adventurous.

This semi-secret garden in south Seattle emulates a traditional Japanese garden using the plants of the Pacific Northwest.

In the middle of an extremely unforgiving and desolate high desert is the most secret military facility in the world.

Rustic natural hot springs in the deciduous rain forest.

A whimsical village of unique treehouses resides in a Washington forest.

Hundreds of glow-in-the-dark objects light up a museum in a historic zinc mine.

No one knows how this Pacific Northwest spruce tree came to have so many trunks.

Tiki luxury on Nob Hill.

These delicate buggers are some of the rarest fossils that have bubbled up from the Tar Pits.