What Happened Here?

I took this photo in May at Columbian Park while on a field trip with my fifth graders. I am not sure just what happened!

EK is all right but you begin to see the distortion on GH's head as it is too far to the right. Poor AY is totally missing from the waist up (I think the rest of her is the smokey yellow miasma to the far right) and P's body from the waist up is no longer centered over his body.

I have never taken a photo quite like this before!