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

Hot springs monkey spa in the middle of Hell's Valley.

Medicinal spa created with the discharge from a geothermal energy plant.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

A bizarre house filled with an astounding array of collections.

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

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.

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

An exquisite tunnel of cascading flowers.

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

Rippling sand dunes frozen in the Arizona rock.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

An abandoned 1920s school with a mysterious history.

Hikers can still stroll beneath the long conveyer of this abandoned mining facility hidden in a West Virginia river gorge.

The "mysteries" of this quintessential roadside oddity were almost destroyed by neglect but were saved by fans of kitschy wonder.

This abandoned amusement park was built on a site with a dark history.

The granite head appears to be deep in thought and half buried in the ground.

The only way to visit this old resort hotel is with scuba gear.

Massive volcano in the Andes is the farthest point from earth's center.

A spring-fed pool so deep it's used for scuba diving as well as swimming.

An oddities shop packed with twisted treasures inspired by Oscar Wilde and Edgar Allan Poe.

A Prada store in the West Texas desert that is never open for business.

An enormous pink granite batholith, long attributed with spiritual powers by the Tonkawa Indians.