I'm not sure how this one would rank as a stand alone fight. Certainly exciting and entertaining, in and of itself, but it's more significant for the ensuing reign of Muhammed Ali.

     Sonny Liston was a much feared fighter. Liston was a street thug who had been arrested over 100 times; after turning pro in 1953, he rapidly ascended the heavyweight ranks, leaving a stream of knockout victims in his wake that included Cleveland Williams, Nino Valdes, Zora Folley and Eddie Machen. He was the greatest heavyweight of the late 1950s, but the champion - Floyd Patterson - avoided him at all costs for almost four years.

     And with good reason: when they fought, first in 1961 and then again on September 25, 1962, Liston knocked him out in the first round each time. When Liston fought the 22-year-old Cassius Clay, it was believed that he would not only knock out the "Louisville Lip," but also seriously hurt him.

The most famous image in sports in the 20th century? Probably this one: the fury of Ali as he stands over Sonny Liston.

     The agile Clay scored repeatedly with jabs and combinations to Liston's head and easily dominated the first four rounds. In Round 5, Clay was temporarily blinded by a foreign substance that was used on Liston's cuts. But by the next round, Clay had recovered his vision and resumed control and Liston had had enough; he quit before the seventh round claiming an injured shoulder. Boxing had a new world heavyweight champion.

     After this victory, Clay publicly announced his conversion to the religion of Islam and change of his name to Muhammad Ali.

     Ali granted Liston a rematch, and knocked him out in 114 seconds in Ali-Liston II on May 25, 1965. Muhammad Ali looking down on the unconscious form of Sonny Liston, refusing to let the referee begin the final count, is also in and of itself one of the classic moments in sports history.