The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.

More than five miles of underground passageways.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

This shifting North Carolina sand dune is an odd little desert surrounded by oceanic forest life.

Most-visited and most-photographed slot canyon in the American Southwest.

A motel dedicated to Southwestern nostalgia.

The highest point in Arizona is an oddly snow-topped peak within the otherwise arid state.

The story of Two Guns, Arizona could easily be described as a Shakespearian tragedy on Route 66.

A pair of giant roadside arrows are all that remains of a former Route 66 trading post.

This stretch of beach along California's central coast is a busy highway for the largest seal in the northern hemisphere.

A massive volcanic plug is now a protected area that hosts a number of bird species.

A second generation sun-powered marvel lights up the night.

A herd of 150 bison live on California's Santa Catalina Island and are at the heart of an ongoing debate between environmental protection and economic expansion.

The oldest lighthouse on America's west coast no longer needs keepers, yet they maintain the site anyhow.

This giant temperature attraction created some giant electric bills.

Elephant seals and sea lions have turned the abandoned buildings on this island into their endangered love shack.

Finally the worlds of UFO enthusiasts and beef jerky lovers have come together in this roadside shop.

A New England-style lighthouse along California's beautiful Highway 1 gets a re-do.

A B&B on a Victorian lighthouse station in San Francisco Bay.

Once close to extinction, there is no shortage of elephant seals on the beaches of Año Nuevo State Park.

A dwindling menagerie of anthropomorphic oil derrick animals still dot the barren California landscape.

A "haunted" landmark on the coast of Southern California.

The unbelievably opulent home built for an infamous newspaperman.