Caeleb Dressel sets world record of 49.50 in men's 100m butterfly semis

Caeleb Dressel of the United States starts during the men's 100m butterfly semifinal at the Gwangju 2019 FINA World Championships in Gwangju, South Korea, July 26, 2019. Dressel sets a new world record with 49.50 seconds. (Xinhua/Xia Yifang)