This castle-like building in Manhattan helped destigmatize cancer in the 19th century.

A hands-on traveling collection of the innovative devices of yesteryear.

The original toys that inspired the beloved children's stories are on display at the New York Public Library.

A garment factory hides a small Dominican eatery in the hallway to its freight elevator.

More gold than anywhere else, ever.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

Prove you deserve to be fed by Kenny Shopsin.

The crown jewel of the Queens Museum is a nearly 10,000-square-foot architectural model of the city originally built for the 1964 World's Fair.

Commemorating the spot where the famous scientist fed his pigeons.

There must be a pun in this haystack somewhere...

An odd, ancient window that may have once been part of a brutal prison is embedded in the side of New York's Police Plaza.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

A New York garbage depot holds a secret collection of weird and wonderful refuse.

Everyone from Mark Twain to Teddy Roosevelt has a pipe hanging from the walls of this historic chophouse.

An unassuming secret door once led to a legendary watering hole.

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

A clock set into the concrete outside a Manhattan jeweler has been telling time underfoot for over a century.

This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

Hidden in an ordinary Midtown building is a one-room museum dedicated to the greatest escape artist.

This semi-hidden Manhattan restaurant is based out of a loading dock.

This speakeasy continues the Prohibition-era legacy of Harlem's jazzy Swing Street.

The "Seinfeld" diner.

Lady Liberty's first beacon of enlightenment is now displayed in a museum near the statue.

One of the only single-person private gravesites in New York City.