Katie Ledecky, who turned 15 in March, is the youngest member of the powerful U.S. swim team and a newcomer on the international scene.
And now, the newest owner of a gold medal.
Ledecky, of Bethesda, took the lead by the 150-meter mark and was on world-record pace through 750 meters, winning the women's 800-meter freestyle in 8 minutes, 14.63 seconds.
It was the second-fastest time in history, behind only Rebecca Adlington's world-record mark when she won the event four years ago at the Olympics. Adlington, of Britain, took the bronze Friday night at the Aquatics Centre.
Ledecky's margin of victory was especially notable: 4.13 seconds. She broke...