The world's largest indoor go-kart racetrack is hiding in Connecticut.

A religious-themed park filled with folk art to bring biblical stories to life that fell into disrepair and now being restored.

Hidden deep within New Jersey Pine Barrens is a massive graffiti wonderland.

Series of storm drains connected to a dark urban legend.

A mysterious air force base built to resemble a Long Island fishing village.

A 19th century hat factory still stands as a crumbling ruin in upstate New York.

This Queens hospital has stood abandoned for almost 20 years after its patients were secretly relocated in the dead of night.

Decades after testing the polio vaccine on unwitting patients, this historic mental hospital sits in ruin.

A stunning, two-tiered waterfall made famous by poets, artists and the legend of a ghost dog.

This Manhattan museum houses one of the largest collections of Spanish art and manuscripts outside of Spain.

These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

A long abandoned hospital building on the outskirts of NYC.

This enormous abandoned factory is now a makeshift graffiti gallery.

Beneath the mossy overgrowth covering this once-sprawling campus lies decades of history and the secrets that come with it.

This eclectic sculpture garden in Brooklyn, home to a bizarre collection of art, was once a run-down junkyard.

This striking arch, one of the first architectural elements constructed in Prospect Park, was recently restored to its original glory.

A Jewish deli run by Yemeni Muslims in an Afro-Caribbean neighborhood is quintessential Brooklyn.

A beautiful collection of architectural ornaments rescued from demolished New York City buildings.

Empty, but not abandoned, this cavernous Brooklyn loading dock was once considered the largest individual building in the world.

Abandoned power station once home to a squatter community, now being developed into an arts center.

Just your average Marie Antoinette–themed speakeasy in an abandoned 19th-century subway tunnel.

One of New York's best collections of pinball is hidden in a secret bar in the back of this laundromat.

A shrine to a skeleton saint in the city of angels.

A "Titanic" superfan changed his name to Jack and set up this strange shrine to the blockbuster, complete with Korean food and Tarot readings.