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

First a horse rendering plant, then a 19th century landfill, this beach is full of glass from thousands upon thousands of broken bottles.

Home to the infamous "Typhoid Mary" and the worst loss of life in New York's history prior to September 11, 2001.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

Bowl in splendor, if you're lucky.

Abandoned 19th century homes once occupied by naval officers, soon to be demolished.

In the middle of downtown Brooklyn lies a 165 year old secret hidden right below the surface (closed to the public indefinitely).

Why have you never heard of the second most popular tourist site in New York?

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

Vacant Beaux-Arts buildings that serve as reminders of a beach town’s glory days.

When ecosystems collide in the arid Southwest.

Mysterious rocks that ring musically when struck.

World's first "penitentiary," meant to be humane, drove men insane.

This naturally-sourced hot spring is now home to a clothing-optional resort.

Ruins of a once-opulent grand Victorian resort.

An emerald-green grotto just a short trip from Austin.

Ruins of a Carnegie family mansion on Cumberland Island.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

Remnants of a storybook amusement park hidden behind a strip mall.

The United States Capitol's former columns still stand.

At 207 feet, one of the world's longest continuous escalators.

One of the oldest living oak trees in the Southeast.

Settled in 1696, abandoned after the Revolutionary War.

Ruins of a once-prized railroad station in New York.