Michael Phelps earned his 20th and 21st gold medals on Tuesday night in Rio, soaring to victory in the men's 200-meter butterfly and men's 4 x 200-meter freestyle relay events. But as he stood during the national anthem to receive the first of the two medals, you may have seen him do something peculiar: burst out laughing.
As you can see in this clip on YouTube, Phelps appears to fight back tears as he stands at the center of the Olympics podium after his win in the butterfly race, when suddenly, he looks to his left and cracks up. And later, at the end of the song, he laughs again and points into the crowd at something off-camera. So, uh, what the hell was so funny?