The legendary building that needed ghostly approval before being built.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

An emerald-green grotto just a short trip from Austin.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

James Turrell's total color immersion art installation, hidden on the top floor of a luxury handbag shop.

The neon signs from Las Vegas' past find their final resting place at this unusual graveyard.

On the Oregon coast there is a natural hole that seems to be draining the sea.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

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

Rippling sand dunes frozen in the Arizona rock.

A kaleidoscopic warehouse-maze of handmade neon signs.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A psychedelic labyrinth on the San Francisco bay.

This airfield played a key role in both World War II and the Cold War.

800 apricot trees honor Silicon Valley's agricultural history.

In 1998, Larry Page and Sergey Brin briefly ran their fledgling company from this Silicon Valley garage.

Exquisite irises bloom every spring in this hillside garden.

At night, this glittering musical tunnel draws skaters and photographers.

This massive redwood tree has stood in Northern California for nearly 2,000 years.

This 19th century train workshop is a treasure trove of railroad history.

On the summer solstice each year, shadows align with a 14,000 square foot painting to reveal a secret message.

This extravagant Art Nouveau rest stop features a million-dollar view of the Columbia River.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

The second largest waterfall by volume in the U.S., Willamette Falls is outdone only by Niagara in the amount of water that is pushed northward.