During the 1974 Academy Awards ceremony, host David Niven was introducing Elizabeth Taylor, who was presenting the award for "Best Picture," when screams erupted from the audience. Niven turned around to see streaker Robert Opel running across the stage, flashing a peace sign. Opel later revealed that he had sneaked through the security checkpoint with a friend's press pass and waited backstage for the final envelope to storm the stage. When he went back to…