A 1924 aerial photograph taken by a Manhattan map-making firm purports to document evidence of submarine activity in the Hudson River near Croton Point. According to Ellen NicKenzie Lawson's book Smugglers, Bootleggers and Scofflaws: Prohibition and New York City, the image shows "two submarines below the surface of the Hudson River, each 250 feet long and 600 feet apart." The photograph emerged …