This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

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.

A 140-year-old castle with underground caves hidden in San Francisco.

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

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

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

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

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

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

A snapshot of the city's fascinating voodoo culture.

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

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

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

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

A psychedelic labyrinth on the San Francisco bay.

A huge musical instrument played by the ocean.

During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.