America's most famous piece of self-built architecture.

A trash dump made beautiful by nature's power.

The ghostly remains of an accidental sea.

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

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

It should come as no surprise that the best view of the Hollywood sign is from Batman's lair.

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

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

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

Dramatic river bend surrounds a natural red-rocked pedestal.

A 140-year-old castle with underground caves hidden in San Francisco.

This faux-seedy Japanese arcade is made up to look like a maze of alleys straight out of a cyberpunk dystopia.

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

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

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

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

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

Rippling sand dunes frozen in the Arizona rock.

A psychedelic labyrinth on the San Francisco bay.

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

A huge musical instrument played by the ocean.