As Usain Bolt gets ready to step into retirement, a closer look at the amazing sprinter's 10 greatest races

Was it his record-setting 100 meters at Berlin in the World Championships? Was it breaking Michael Johnson's "unbreakable" 200-meter mark? Was it his feat of winning a third straight Olympic 100 meters race in Rio? As Usain Bolt gets ready to run in his final World Championships before retiring, we rank his 10 greatest feats. My story for ESPN.com: http://www.espn.com/athletics/story/_/id/20244888/iaaf-world-athletics-championships-2017-best-performances-usain-bolt-career