Evretou building 9a: this house too was being used as a straw (and sand or cement?) store; however, the thing that grabbed my attention was this gaping hole in the wall and floor.

The material surrounding the hole still sturdy, the wall seems to have been punctured, the floor breaking up and falling down with it (one benefit for people studying it being the "fan" of material displaying the many phases of its construction, most visible in the photo of Evretou building 9d). I still want to know: who or what did this (with what, how) and why?