American swimmer Katie Ledecky has broken the world record in 400-metre freestyle, giving her country its first swimming gold of the Rio Olympics. The 19-year-old clocked 3:56.46 to better the previous record of 3:58:37, also held by her. Great Britain’s Jazmin Carlin finished second followed by US’ Leah Smith.
Katie Ledecky breaks 400m freestyle world record
