A crumbling hospital from the 1850s on Roosevelt Island.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

One of only two commuter aerial tramways in the United States.

These mystical miniature houses bring a touch of magic to the New Jersey woods.

The haunting, dilapidated remains of a former poorhouse on Staten Island's Greenbelt.

The wooden octagon in which Huckleberry Finn and A Connecticut Yankee were born can still be visited in upstate New York.

The little-known final resting place of one of America's greatest writers.

The mastermind behind this palatial hotel perished on the Titanic weeks before its grand opening.

This island castle contains enough secret passageways to support a season of Scooby-Doo episodes.

Lady LeWinDa Milkzalot showcases Lewis County's dairy farming heritage and boasts an impressive rotation of seasonal outfits.

Hundreds of glow-in-the-dark objects light up a museum in a historic zinc mine.

The summit Roosevelt conquered before he descended to become The Chief.

This former theme park in New York's Adirondack Mountains fell into ruin before being resurrected as a state-run campground

The dairy farm in upstate New York where nearly half a million people gathered for three days of peace and music in 1969.

A pair of 19th-century granite markers symbolically record where the state boundaries of New York, New Jersey, and Pennsylvania intersect.

A winding, cliffside stretch of road overlooking the Delaware River.

This outpost of America's most popular fast-food restaurant is housed inside a palatial mansion.

A century ago, aspiring socialites climbed on this cement beast with the hopes of marrying a millionaire.

An unrealized dream to wirelessly electrify the entire Earth.

A former poultry store that looks like a giant duck and is one of the "seven wonders" of Long Island.

The site of a tragic massacre that spawned a multimedia franchise.

Four cars from the old system were once on display, but were removed in 2014.

Waterway populated with abandoned projects, including a submarine.

East meets West in this Japanese-style garden featuring plants native to Maine’s Mount Desert Island.