This bomb was one of those dropped during the first daylight bombing attack on London by a fixed-wing aircraft. Prior to this the bombs had been dropped from Zeppelins. Just before noon the bomb broke through the roof into the girls' class taking place on the top floor, through that into the boys' classroom, and through that into the infant class where it exploded. 18 children were killed.
Fifteen of the children were buried in a mass grave at the East London Cemetery.The Guardian has a good photo.
Sources for more info and pictures: Idea Store, Mayflower, Find a Grave.
