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

A trash dump made beautiful by nature's power.

A layered tribute to the work of mosaicist Isaiah Zagar.

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

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

Try not to get slimed in Tribeca.

A one-of-a-kind collection of a unique medium.

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

A snapshot of the city's fascinating voodoo culture.

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

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

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

World's first "penitentiary," meant to be humane, drove men insane.

A crumbling hospital from the 1850s on Roosevelt Island.

Rippling sand dunes frozen in the Arizona rock.

A psychedelic labyrinth on the San Francisco bay.

World's largest collection of serial killer artwork and other macabre exhibits.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

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