The USA's Katie Ledecky continues to make history at the World Championships in Kazan after setting a new world record on her way to gold in the 1500m freestyle final.

The 18-year-old broke her own previous record in the heats with a time of 15:27.71, but she was able to better it in today's showdown.

Immediately, Ledecky took half a metre off the rest of the field from her dive, and she went two seconds under world-record pace at the 300m mark.

The teenage swimmer's dominance never wavered as she comfortably took gold in 15:25.48, while New Zealand's Lauren Boyle and Boglarka Kapas of Hungary earned silver and bronze respectively.