Well here is my opinion, the only person to stop Muhammad Ali, that was on Oct 2 1980, his name was Larry Holmes, who by the way was in his prime, Ali was way passed his. A certain poster stated that Henry Cooper floored Ali with one punch, that was on June 18 1963, before Ali won the title from Sonny Liston in 1964. And before that Ali was decked by Sonny Banks in 1962, but more importantly, Ali showed heart, he got up to win both fights. How come no one brings up Ali vs Cooper II, on May 21 1966? Is it because he won? Sour pusses are always looking for the negative. I think and believe personally that Ali from the peak years of 1964-1967 does not get knocked out by anybody, too much speed, great footwork, catlike reflexes, and no indications of Rope A Dope, his stamina was unending. Maybe there was a reason that Yank Durham did not want Joe Frazier to fight champion Muhammad Ali in 1967. If 1967 Ali had fought prime Joe Louis, he would have not made the same error that Billy Conn made in 1941. And last if you detest Ali, be man enough to say you do, do not be hiding behind a jolly green giant that it is near impossible to pronounce their names or the one hit wonder current champion that prefers snow over fighting, his nose needs it.