high school in arkansas. protests have produced some of the most enduring images. in 1989, after a massacre by chinese troops in tiananmen square, one man squared off against a line of tanks. his identity has never been known. his brave stand, never forgotten. pictures of war have had immense impact from the birth of photography. the civil war, world war i, world war ii, in vietnam, modern media gave them even more power, a monk setting himself ablaze. a vietcong assassin being executed by a south vietnamese officer. a 9-year-old girl running from napalm. she spoke many years later about that haunting scene. >> it's my message to people when they see that picture, try not see her as crying out in