Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

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

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

A crumbling hospital from the 1850s on Roosevelt Island.

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

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

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

A psychedelic labyrinth on the San Francisco bay.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

A bizarre house filled with an astounding array of collections.

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

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

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

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

On Japan's Tashirojima Island, cats are king.

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.

An eerie, derelict amusement park in Berlin.

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.

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.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.