Along with the rest of industrial Upper Silesia Tychy was occupied by Nazi Germany forces after the invasion of Poland and annexed into the Third Reich, while many of its inhabitants who were not expelled or exterminated were forced to change their nationality to German in order to comply with the racist policies of Nazi Germany. Mass arrests and executions of Polish activists and former Polish insurgents of 1919–1921 were carried out in the first days of the occupation in September 1939. As early as September 3, 1939, the Germans murdered several Polish residents of the city, of whom 13 were later identified, the youngest was 16 years old. The Germans also carried out manhunts of Polish insurgents who were hiding in the forest between Tychy and Mikołów, and established and operated a "Polenlager" forced labor camp for Poles in the city, and the E701 labor subcamp of the &lt;a href="Stalag%20VIII-B"&gt;Stalag VIII-B/344&lt;/a&gt; prisoner-of-war camp in the present-day Czułów district. The last public execution was carried out on September 22, 1944, when five members of the underground Polish resistance movement were killed. Tychy received minimal damage during the invasion because most of the nearby fighting took place in the Mikołów-Wyry area. In the final stages of the war, in 1945, a German-conducted death march of thousands of prisoners of the Auschwitz concentration camp and its subcamps passed through the city towards Gliwice.