Muhammad Ali during a training session at Chris Dundee's 5th Street gym in Miami Beach in 1971.
Chris Smith—Hulton Archive/Getty Images
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Cassius Clay, who would change his name to Muhammad Ali, at 12 years old.
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Members of the U.S. Olympic boxing team gather for a group photo. From left: Nicholas Spanakos, 22, featherweight; Jerry Armstrong, 24, bantamweight; Humberto Barrera, 18, flyweight; Edward Crook, 31, light middleweight; Quincy Daniels, 19, light welterweight; Harry Campbell, 22, light middleweight, and Cassius Clay, 18, light heavyweight.
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The winners of the 1960 Olympic medals for light heavyweight boxing on the winners' podium in Rome: Cassius Clay (center), gold; Zbigniew Pietrzykowski of Poland (right), silver; and Giulio Saraudi (Italy) and Anthony Madigan (Australia), joint bronze.
Central Press/Getty Images
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Clay, soon to be known as Muhammad Ali, bicycles near his parents' house in Louisville, Ky., circa 1963.
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Ali is pictured with his mother, Odessa, and his Father Cassius and brother Rudolph in the background at his family home in Louisville, Ky., circa 1965.
Pictorial Press Ltd/Alamy
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Ali talks to admirers and relatives in the basement of an arena before a fight on Oct. 7, 1961, in Louisville, Ky.
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Ali arrives at the Piccadilly Hotel in London, circa 1966.
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Ali leaves a federal court in Houston after a jury found him guilty on charges of refusing to be inducted into the U.S. armed forces on June 20, 1967. Ali contended that he was a Nation of Islam minister and not subject to the draft.
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Ali peers around a 'Stop World War III' picket sign before addressing an anti-war group that had assembled to protest the Vietnam War on June 23, 1967 in Los Angeles. The group of thousands staged a march to the Century Plaza Hotel where President Johnson was being honored which ended in a bloody battle with the police.
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Muhammad Ali with his second wife, Belinda Boyd, and their children, daughter Maryum and twins Jamillah and Rasheda, in 1971.
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Ali speaks to the press during a pre-fight weigh-in at Madison Square Garden in New York City in March 1971 ahead of what would become known as The Fight of the Century where Ali would go 15 rounds with champion Joe Frazier.
John Shearer—Time & Life Pictures/Getty Images
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Four years later in October 1975, Ali and Frazier would face off for a third and final time in the Philippines in the fight that became known as "Thrilla in Manila".
Lawrence Schiller—Getty Images
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Ali defeated Joe Frazier once more in the "Thrilla In Manila". This fight surpassed their earlier bouts, and became one of the most well-known heavyweight fights ever.
Nick Wheeler—SIPA USA
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Ali was diagnosed with Parkinson's disease in 1984. He is pictured here at a hospital in New York City on Sept. 21, 1984, following four days of tests. Ali said, "I'm always tired," following his diagnosis.
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Ali traveled to Beirut in February 1985 to help secure the release of Westerners held hostage by extremists.
Francoise De Mulder—Roger Viollet/Getty Images
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Muhammad Ali receives Medal of Freedom Award on Oct. 27, 1986.
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The former First Family poses for a photo with Muhammad Ali at the White House Millennium Dinner on Dec. 31, 1999.
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Muhammad Ali prays on a gazebo at his farm in Berrien Springs, Mich., on Sept. 10, 1996.
Walter Iooss Jr.—Sports Illustrated/Getty Images
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Muhammad Ali and actor Michael J. Fox before the start of a Senate subcommittee on Labor, Health, Human Services and Education hearing on Parkinson's Disease on Capitol Hill in Washington on May 22, 2002.
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Ali's daughter Laila won the WBC/WIBA Super Middleweight Championship Bout with a 3 round TKO against Erin Toughill in Washington on June 11, 2005.
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Muhammad Ali at the Crystal Award ceremony at the World Economic Forum in Davos, Switzerland, on Jan. 28, 2006.
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