Katie Ledecky of the USA demolished her own world record as she retained the women's 1500m freestyle world title in Tuesday's final.

Having broke the world record in Monday morning's heats, the 18-year-old triple world record-holder knocked 2.23 seconds off her own personal best to clock 15 minutes, 25.48secs.

New Zealand's Lauren Boyle took silver at 14.66secs back while Hungary's Boglarka Kapas came home for bronze at 21.61secs adrift.
Source: AFP