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

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

James Turrell's total color immersion art installation, hidden on the top floor of a luxury handbag shop.

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 enormous, inside-out glass globe built in 1935.

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.

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

A snapshot of the city's fascinating voodoo culture.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

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.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

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

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

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

A crumbling hospital from the 1850s on Roosevelt Island.

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

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

La Monte Young and Marian Zazeela's "Dream House" will immerse you in an ever changing world of sound and light.

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