Elevated freight railway turned wildly successful urban park.

Try not to get slimed in Tribeca.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

A crumbling hospital from the 1850s on Roosevelt Island.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

The first and only carousel with a lineup entirely of insects.

A former connection to City Island, it has been abandoned since the 1930s.

The famous author's cottage hideaway.

The loneliest island in New York.

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

A ruined mansion hidden in the woods of the Hudson Valley, home of a tragically doomed romance.

This abandoned cemetery is crumbling into ruin, exposing the artifacts and bodies buried there.

This abandoned factory on the Hudson River once churned out a million bricks a week.

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

Dogs, cats, horses, monkeys, frogs, and fish are laid to rest at the second-oldest pet cemetery in the U.S.

A cave on the Maryland border where civilians took refuge during the bloodiest battle of the Civil War.

Built by the patriotic residents of Boonsboro in a single day.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

A mammoth pair of Civil War artillery guns abandoned out in the forest.

Remains of a historic fountain that was mysteriously lost in the demolition of a D.C. traffic circle.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

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