Muhammad Ali 5

Ali is the greatest boxer to ever live. In his prime, that is before he was suspended from boxing, he was untouchable. It was virtually impossible to land a solid punch on Ali when he entered the sport, and his hand speed was unrivaled. Although there have been many boxers that could hit harder then Ali, none could avoid a punch like he could. If it wasn't enough for him to have the fastest feet and quickest jab of all time, he was possibly the smartest boxer to ever live. His boxing instincts are what allowed him to be a great boxer even after he lost his foot speed, which is how he beat Foreman. He is the greatest boxer to ever live, and he would have beaten any boxer prior to his era, and any boxer since his era. Also despite what some people are saying on this site, Ali never boxed or sparred against Rocky Marciano.