Michael Phelps won a record 19th Olympic medal as the United States took 4x200m freestyle relay gold.
The 27-year-old, who swam the anchor leg as the Americans won in a time of six minutes 59.70 seconds, now has 15 golds to his name.
Ryan Lochte put the US team in total control with a blistering first leg and they finished well ahead of France in second and China third.
Phelps overtakes Russian gymnast Larisa Latynina, who won 18 medals.
Just minutes before the relay victory, Phelps had claimed his 18th Olympic medal with a silver behind South Africa's Chad le Clos in the 200m butterfly.