Ref post 13, it's not surprising that several unexploded bombs were discovered relatively closely together because some air raids carried out by the Luftwaffe lasted hours with large amounts of ordinance dropped. I believe that one of the longest air raids which my father and other family members were subjected to lasted for around 10 hours although there were lulls in the intensity during this period. The ordinance dropped is believed to have included thousands of incendiary bombs, significant numbers of H.E. and also Phosphorous (for illumination of target).