From their experiences during the hostilities, the Polish people realized that occupation by the Nazis would be grim. But no one ever imagined that it would be an uninterrupted succession of crimes, committed not only in cold blood and with premeditation but with the utmost viciousness and ingenuity. True, the very first days of the war had shown that the Nazi invader was devoid of any humanitarian feelings and had no respect for international conventions or rules for the conduct of war. In its first raids on Polish towns, the Luftwaffe had bombed residential areas without any delusion that they were military objectives. Any idea that perhaps these were mistakes was dispelled by the dropping of fragmentation and incendiary bombs on small suburban settlements and on hospitals and hospital trains clearly marked with red crosses on their roofs. There was also the strafing of defenseless civilians escaping along the roads and fields from the burning villages and towns before the rapid advance of the Germans. Every day brought reports of atrocities being committed by the Wehrmacht in the territories they had overrun. There was news of the shooting of soldiers who had been taken prisoner and of the ill-treatment and slaughter, on any excuse or even completely without any justification, of innocent civilians, particularly Jews.