While driving 50 mph on a smooth road on an overcast, 65 degree day, my rear sunroof spontaneously exploded. It sounded like a gunshot, glass flew off of my car and some fell in the car (the screen under the sunroof was closed almost all the way, containing most of the glass that fell in). I pulled over to check it out, everything else was ok, tires, etc. The only issue was the gaping hole in the sunroof that had exploded.