When Cassius Clay, now known as Muhammad Ali, defeated Sonny Liston
(above left), he was the youngest boxer ever at age 22 to take the title
from a reigning heavyweight champion.

Muhammad Ali (born Cassius Marcellus Clay, Jr.) is a former boxer and three-time World Heavyweight Champion, who is widely considered one of the greatest heavyweight championship boxers. As an amateur, he won a gold medal in the light heavyweight division at the 1960 Summer Olympics in Rome. After turning professional, he went on to become the first boxer to win the lineal Heavyweight Championship three times.