In the final seconds of the women's 400m sprint final, Bahamas runner Shaunae Miller beat the reigning champion by diving (or falling?) across the finish line.
Miller and London Olympics gold medalist Allyson Felix were side by side for the final metres before Miller literally put her body on the line.
— Deji Kofi Faremi (@deejayfaremi) August 16, 2016
It's not against the rules to dive, as long as a part of your body crosses the finish line while staying in your lane.
After the race, Miller said: "This is the moment I have been waiting for, I just gave it my all."
Champion sprinter Michael Johnson says Miller didn't dive, she was bracing herself for a fall.
Either way, here it is in photos.