2) Muhammad Ali (56W-37KO-5L)
Muhammad Ali, born Cassius Marcellus Clay, Jr., January 17, 1942, is a legendary American boxer who has won three heavyweight championships in his career. He is famous for his quote "float like a butterfly, sting like a bee," which aptly described his boxing style. It was unusual that Ali, a heavyweight boxer, relied on foot speed and quickness to avoid punches from his opponents. He has fought with many other outstanding boxers such as Ken Norton, Sonny Liston, George Foreman, Leon Spinks and Joe Frazier. There is no doubt that Ali was one of the most exciting, outspoken, and undefeated boxing sensations in his prime. However, later in life, Ali developed Parkinson's disease.