Kammala wannan jumla: A farkon Yaƙin Duniya na II a 1939, bayan roƙon Franklin D. Roosevelt, Shugaban Amurka mai tsaka tsaki a lokacin, manyan ƙasashen Turai, gami da Burtaniya da Jamus, sun yarda ba za su yi ruwan bama-bamai a kan fararen hula a wajen yankunan yaƙi ba: Burtaniya ta yarda da cewa sauran ƙasashe ma sun guji. (duba manufofin kan fashewar bam a farkon Yaƙin Duniya na II). Duk da haka, wannan ba a girmama shi ba, kamar yadda masu yaƙi na bangarorin biyu a cikin yaƙin suka ɗauki manufa ta jefa bama-bamai ba tare da nuna bambanci ba a biranen abokan gaba. A lokacin yakin duniya na biyu, birane kamar Chongqing,
Warsaw, Rotterdam, London, Coventry, Stalingrad, Hamburg, Dresden, Tokyo, Hiroshima, da Nagasaki sun fuskanci harin bam na sama, wanda ya halaka gine-gine da yawa kuma ya kashe dubban fararen hula.