Long before Paul Newman and Robert Redford immortalized them on screen, Butch Cassidy and the Sundance Kid captivated Americans from coast to coast. In the 1890s, their exploits robbing banks and trains in the West -- and then seemingly vanishing into thin air -- became national news and the basis of rumors and myth. But who were Robert Leroy Parker and Harry Alonzo Longabaugh? How did they come together to form the Wild Bunch gang? And how did they manage to pull off the longest string of successful holdups in history while eluding the Pinkertons, the nation's most feared detective force? Separating fact from fiction, this program explores the last pair of outlaws to flee on horseback into a setting sun.