KatIe Ledecky (swimming)
The US teenager has laid waste to the history books since emerging onto the world scene at the London 2012 Olympics, when she won 800m freestyle gold.
She has already collected one gold and one silver in Rio and will expect to pick up around three more golds before the event comes to an end.
Nobody is better in freestyle events, and she appears to have made no enemies - a rare feat in a cut-throat sporting world.