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

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

This nature center has one of the largest collections of native raptors in the Pacific Northwest.

A massive sea stack famous for its appearance in The Goonies.

Only known mainland rookery of the threatened Stellar sea lion.

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

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

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

The fifth-longest natural arch in the world, and the longest outside China.

A desert settlement founded and later abandoned by Hawaiian members of the Church of Jesus Christ of Latter-day Saints in Utah's Skull Valley.

A Mars simulation in the southern Utah desert.

This quiet park's strange sedimentary spires were named after Kodak's color film.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

A house carved into a rock in the 1940s.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

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

This rugged area of red rocks and arches is often considered one of the most beautiful places on Earth.

This geothermal hot spring hides beneath a slowly growing mineral dome.

The highest point in Washington state is a volcano covered in glaciers.

Essence of hound's tongue and tincture of bloodroot are just the tip of the herbalist iceberg at this beautiful, impressively-stocked apothecary.

Twin Peaks' real life Double R Diner has been restored to its damn fine television look.

The longest and widest floating bridge in the world.

A small town market proudly displays numerous taxidermied animals along its walls.

A rare tour of a commercial jet assembly plant, held inside one of the largest buildings in the world.