The Washington Opera plans to simulcast a performance of “Porgy and Bess” on the National Mall. “The 2 p.m. performance will be transmitted live from the Kennedy Center Opera House and shown on a gigantic video screen, 18 by 32 feet, that will be located near the Capitol, with speakers set up for sound. Although large screens have been used to let audiences view close-ups of musicians while they were playing on the Mall, this is believed to be the first time that a performance originating elsewhere will have been transmitted there live.”