Since the death of Osama Bin Laden, this has become the photo to commemorate the historic event. It's been analyzed, scrutinized, and just about everything else-ized, as commentators have tried to figure out exactly what was occurring at that moment, and what was going through the mind of each person in the room.
"Those were 38 of the most intense minutes. I have no idea what any of us were looking at that particular millisecond when the picture was taken... I am somewhat sheepishly concerned that it was my preventing one of my early spring allergic coughs. So it may have no great meaning whatsoever."