His domination complete, Michael Phelps hit the wall, took a couple of deep breaths and then put up four fingers. 

AP Photo/Natacha Pisarenko

The four fingers signified Phelps' fourth straight Olympic victory in the 200-meter individual medley. No swimmer has ever done that in Olympic history.

It's also his fourth gold medal of the Rio Games, giving him an astonishing 22 in his career.