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

This abandoned ironworks was once the most important military supplier in America.

"A hideous albatross in the Hudson River Valley."

This mouldering abandoned mental hospital was once a center for progressive healing.

Neon signs that grace the windows of Bergdorf Goodman's and Tiffany & Co. come from this studio in Brooklyn.

This one-man homegrown eatery may be the world's most exclusive restaurant with its five-year waiting list.

Toxic waste disaster that founded the Superfund program.

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

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

An abandoned horticulture institute gloomily presides over rows of derelict and vine-wrought greenhouses.

One of only two remaining Victorian-era greenhouses in New York.

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

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

Buffalo's abandoned concrete grain elevators are getting a second life.

An abandoned tuberculosis hospital moulders on into an uncertain future.

A beautiful, historic location open to the public.

The second largest maple syrup producer in the U.S. runs a high-tech operation.

A nearly 100-year-old dining car in upstate New York embodies the golden age of roadside dining.

The original Uncle Sam was actually a New York meatpacker who is buried under this historic grave.

The world’s largest underground marble quarry is hiding in Vermont.

The first evidence of some of the Earth's earliest life was found in this fossilized undersea grotto.

An unexpected canine grave atop a mountain.

A monument to the military service of America's greatest traitor refuses to even name him.

This throwback amusement park is home to rides and unique storybook figures from the past.