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

This cave was hidden for thousands of years, storing the worldly goods of ancient Native Americans.

This famous Nevada gold mine, once a hotbed of Wild West shenanigans, is now open for tours.

A gothic palace of endless stalagmites and pseudoscorpions waits within one of the world's most beautiful caves.

Preserving the remains of Native American cultures which otherwise would have been submerged behind Hoover Dam.

The drama of nature in full effect in this Nevada State Park.

The illuminated falls are a gem in North Cascades National Park.

The second tallest railway trestle bridge in America.

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

One small town in the Pacific Northwest transformed itself into a Bavarian-themed tourist destination.

This long, dark tunnel is open to hikers, but those without lights are known to get confused even on the straight path.

A bike being "eaten" by a tree is the real Vashon legend behind popular children's book, "Red Ranger Came Calling."

The remains of a former logging boom town, crumbled away in the forest.

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

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