In this preview from the "Art in the Twenty-First Century" Season 6 episode, "Change," artist Catherine Opie discusses her on-going series, "Girlfriends," during a photo shoot for the series with swimmer Diana Nyad in her Los Angeles studio. "Change" premieres Friday, April 13, 2012 at 9:00 p.m. ET on PBS (check local listings). For more information on Catherine Opie, please visit: http://www.art21.org/artists/catherine-opie