On December 30, 1942, 25-year-old Frank Sinatra stepped onto the stage of New York’s Paramount Theatre. On cue, a dozen girls planted in the audience began screaming. Two pretended to faint. Unexpectedly, what began as a publicity stunt unleashed an episode of mass hysteria. Hundreds of other young women joined in the screaming and fainting, and 30 were rushed away in ambulances.