Examining Muhammad Ali's knockout of Sonny Liston 50 years laterOn SI Now, photographer Neil Leifer discusses his iconic photo of Muhammad Ali after his first-round knockout of Sonny Liston in 1965 during the WorldSI Staff|Share on FacebookShare on XAdd us as a preferred sourceOn SI Now, photographer Neil Leifer discusses his iconic photo of Muhammad Ali after his first-round knockout of Sonny Liston in 1965 during the World Heavyweight championship fight.Published May 21, 2015 | Modified May 21, 2015SI STAFFShare on FacebookShare on XHome/Boxing