Roberto Duran, widely regarded as one of the greatest pound-for-pound fighters of all time, celebrated his 60th birthday on June 16. A world champion at lightweight (1972-79), welterweight (1980), junior middleweight (1983-84) and middleweight (1989), the Panama native remains the only boxer in history to win fights in five separate decades. Here's a look at the eight Sports Illustrated cover appearances of Duran's career.