Who are the greatest athletes of all time? Obviously we can only go with the modern era(19th century to present)but they can be from any sport. Off the top of my head I would pick Jordan,Thorpe,Jesse Owens,Pele,Ali and Lance Armstrong. There are def others.
The greatest multi-sport athlete of all time is Jackie Robinson. In addition to his baseball achievements, he was a football running back who averaged 11.3 yards a carry in his junior year at UCLA, was the 1940 NCAA champion in the long jump (and would have been the favorite in that event at the 1940 Olympics if there had been a 1940 Olympics), was a basketball star who led the Pacific Coast Conference in scoring in both his junior and senior years at UCLA. Jimmy Brown wasn't bad as a multi-sport athlete, too.