A stunning, abandoned limestone quarry in southern Indiana provided the stone to erect the Empire State Building.

This abandoned Navy base was transformed into an off-grid alternative living community for thousands of people.

The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.

Abandoned silver mine strewn with wrecked and twisted structures.

If astronomy had a ghost, it would look like this observatory.

An urban forest overtakes what was the greatest failure of utopic urban housing.

Rippling sand dunes frozen in the Arizona rock.

New fungal and bacterial species call this deadly lake home.

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

Giant granite rocks standing end-to-end like a train of circus elephants.

Devilish landscape, once cinema home to giant alien bugs, now derelict roadside attraction.

One of the most unusual geological features, recognizable from a dozen hit movies.

The rocks in this arid basin leave trails of movement behind them.

Eons ago, a rushing lava river formed this pristine passage through solid rock.

A hard-to-reach oasis in a desolate corner of Death Valley National Park.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

A museum dedicated to the alleged Roswell Incident.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

An eatery for UFO seekers on the Extraterrestrial Highway.

This UFO landing strip was created by a charitable Wyoming city that was worried about residents of Jupiter.

Mysterious meeting place for UFO hunters near Area 51.

If you want to take a peek at Area 51, this is legally as close as you're going to get.

This dormant volcanic crater has been converted from a roiling pit of magma to a pleasant hiking spot.

The highest point in South Dakota contains the ashes of Valentine McGillycuudy, the "Holy White Man."