Police say 59-year-old Bobby Jackson left his handgun under the cushion of a chair in the lobby of the World Center Hotel.
He was about to visit the September 11th Memorial Museum next door to the hotel.
Unfortunately for him, a woman sat on the weapon and reported it to managers, who called police.
The gun was registered, but Jackson was not licensed to carry it into New York City.
He is charged with second-degree criminal possession of a weapon and second-degree reckless endangerment.