Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

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

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

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.

Remants of foundations, streets, and streetcar tracks inhabit the cliffs where a landslide occurred in 1929.

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

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

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

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

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.

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

A crumbling hospital from the 1850s on Roosevelt Island.

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

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

Non-profit time travel mart sells goods you would need for a trip through the fourth dimension.

Rippling sand dunes frozen in the Arizona rock.

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

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

A beautiful and abandoned New York subway station from 1904, complete with chandelier.