sentences:  On the day of the outbreak of World War II in September 1939, Chorzów was taken by Nazi Germany.Polish irregulars, mainly Silesian uprising veterans and Scouts, put up resistance to the regular German forces for three days, most of them were murdered in mass executions.Polish property was confiscated, and Chorzów (with the balance of Polish Silesia) was promptly re-incorporated into German Silesia ("Preußische Provinz Schlesien", from 1941 "Oberschlesien"); the Upper Silesian industry being one the pillars of the Nazi Germany war effort.