A bumper sticker is an adhesive label or sticker with a message, intended to be attached to the bumper of an automobile and to be read by the occupants of other vehicles—although they are often stuck onto other objects. Most bumper stickers are about 30 cm by 8 cm (12 in by 3 in) and are often made of PVC.
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Censuring Joseph Stalin at a public meeting, Soviet premier Nikita Sergeyevich Khrushchev was interrupted by a voice from the audience. "You were one of Stalin's colleagues," shouted the heckler. "Why didn't you stop him?"
"Who said that?" roared Khrushchev. There was an agonizing silence in the room. Nobody dared moved a muscle. Then, in a quiet voice, Khrushchev said, "Now you know why.