More info on Muhammad Ali
George Foreman becomes heavyweight champ when he registers a second-round TKO of Joe Frazier in Kingston, Jamaica.
"The Rumble in the Jungle" - Muhammad Ali uses the rope-a-dope to tire out undefeated George Foreman and then knocks him out in the eighth round in Zaire to regain the heavyweight title.
Rocky Marciano is the only heavyweight champ to retire undefeated (49-0). SportsCentury: Rocky Marciano airs Tuesday at 4 pm ET.