Michael Phelps has more Olympic medals (19) and gold medals (15) than anyone else in history. That much cannot be disputed.
But is he the greatest summer Olympic athlete ever? Well, that question might set off a worldwide debate.
Sebastian Coe, a two-time gold medalist in the 1,500 meters and head of the London Games, said Wednesday that Phelps may be the most successful Olympian ever, but that doesn't necessarily mean the greatest.
He said his list of candidates would also include track and field legend Jesse Owens, who won four gold medals at the 1936 Berlin Olympics, and Romanian gymnast Nadia Comaneci, who achieved a perfect score at the 1976 Olympics.
Coe also mentioned a pair of British athletes -- five-time gold medalist rower Steve Redgrave and two-time decathlon champion Daley Thompson -- but left off U.S. track star Carl Lewis, who won nine gold medals and 10 overall.