The lush coastal city of Astoria is riddled with forgotten secret sidewalks.

In a 345-million-year-old cave that's 200 feet underground, dinner awaits.

The world's oldest hologram gallery and the labyrinthine laser laboratory of a holography pioneer.

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

This small-town Connecticut restaurant gives each diner a free book from its vast library.

Eons old volcanic activity created one of the most stunning rock formations in the United States.

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 tiny piece of the Moon is embedded in this stained glass masterpiece.

A morbid secret lies hidden within the beautiful walls of the Boston Athenaeum.

A castle built by an eccentric medieval enthusiast in rural Ohio.

Home to the infamous "Typhoid Mary" and the worst loss of life in New York's history prior to September 11, 2001.

A house carved into a rock in the 1940s.

When ecosystems collide in the arid Southwest.

This free, take-a-book shop seems like a trick but isn't.

Stripes of flowers bloom each spring in a 50 acre rainbow of color.

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

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

Less a museum than a bizarre fantasy world created by artists and engineers.

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

Oh, just a motel on the edge of the desert decorated with thousands of clowns conveniently located next to an abandoned graveyard.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.

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

Canyon walls shrouded in ferns.