US swimmer sets Olympic record in 800m freestyle heats
US swimmer Katie Ledecky set an Olympic record with the fastest time in the 800m freestyle heats on Thursday. The 19-year-old swam the 16-length event in 8 minutes and 12.86 seconds, almost seven seconds faster than anyone else. Having already won three golds and a silver in Rio, Ledecky will compete in the 800m freestyle finals on Saturday.