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

An arsenic-filled pool in the Grand Canyon takes on the appearance of a giant, overflowing pumpkin.

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

A 300-yard long natural tunnel runs through a ridge deep in the Appalachian Mountains.

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

Sniff the Titan Arum's rotting flesh.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

See massive fossils that are over 200 million years old in northeastern Arizona.

Breathtakingly blue walls shimmer inside the "Glacier Behind the Town."

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

This futuristically sylvan church is a glass-enclosed marvel of modern architecture.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

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

Oregon's unexpected high desert, displaying layers of time in a colorful show.

The scuba diving training facility was named for the steam that rises from the cave's chimney.

This natural wonder drops 16 stories straight down through rare flora and streaming waterfalls.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

One part antique store, one part curiosities hodge-podge.

Ride the subways of yesteryear.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

An acoustic anomaly with a mysterious cause.

One person's lost luggage is another person's treasure.