The Walnut Street Theatre, located in Philadelphia, Pennsylvania, is the oldest continuously-operating theater in America. Its first play was The Rivals in 1812, and it went on to host many pre-Broadway tryouts of soon-to-be classics—including Gigi with Audrey Hepburn and A Streetcar Named Desire with Marlon Brando. Technologically innovative, it was the first theater to install gas footlights and air conditioning. In 1976, what major non-theatrical event happened there? Discuss