A bag with a closure adapted so as to prevent theft

A bag with a closure mechanism adapted so as to deter thieves comprises a bag with an opening provided with a closure device, the toggle, puller or the like of which is within the user's field of vision when the closure device is closed and the bag is being carrier or worn by the user. The bag is preferably a backpack. The closure may be a zipper fastener, the toggle/puller of which is masked by a flap in the closed position, a drawstring or a plastic sealing system. The bag prevents thieves from using the noise and bustle of a crowd to mask the action of unzipping the bag so as to steal its contents.