this kind of thing hapen in finland
(dont know if this is the picture of it but about the same size rock)
but this what hapen in finland
They were destroying the cliff whit dynamite and they used a cone to insert a sertain amount of dynamitepowder to the holes and then blast them up.
but sombody forgot the cone on the hole (cone had alot of dynamite in it) then boom and the rock flew about 900m away straight through the celing. thank god no-one whas home at the moment…