The firebombing of Tokyo has to be up there as one of the worst atrocities committed during WWII. ~100,000 dead, a million injuries, a million without homes, in 6 hours, on basically civilian targets. The justification for bombing civilians (that the Japanese had put their military industry into people's homes in a sort of "cottage industry") was weak at best. Of course, this took the lessons learned at Dresden and Hamburg and took it to another level. LeMay used up all the incendiaries available to him in the Pacific Theater by the time he was done.