This once-private estate is now a dreamy, meditative garden that's open to the public.

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

This otherwise innocuous bodega was once the headquarters of the most feared assassin's guild in American history.

Three stories above you, your salad is being grown.

A miniature rainforest is growing inside of a Midtown Manhattan office building.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

Hordes of precariously balanced stone figures crowd the shores of the Hudson River.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

A legal loophole makes it possible to get away with murder within this 50-square-mile section of Yellowstone.

Haunted Victorian house that inspired a legendary "Ghostbusters" court ruling.

Astonishing collection of helmets, scientific instruments, and medical models.

Reclaimed by nature, the ruins of Doodletown, New York are remnants of a town consumed by a state park.

The only remaining piece of hull of the most decorated US ship of WWII is this giant name plate.

A backdoor to Machu Picchu that only the most foolhardy infiltrator would attempt to breach.

A massive art collective tries a new take on Brooklyn's DIY music scene—by making it fully legal.

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

Underground vaults of a former brewery beneath Brooklyn's Crown Heights are now used to ripen cheese.