During the invasion of Poland in September 1939, the SS deployed paramilitary units known as Einsatzgruppen to follow advancing soldiers and to begin the process of “pacifying” occupied towns and cities. This effort involved identifying so-called potential resistors in Poland. Three groups of people were singled out: landowners, the intelligentsia, and clergymen. Tens of thousands of civilians, some doctors, politicians, and journalists, were rounded up and arbitrarily sentenced to death. These sentences were carried out not only by the Einsatzgruppen, but also by newly recruited ethnic Germans [Volksdeutsche] from within Poland. Among those murdered were Catholic religious leaders. This image shows a priest awaiting execution by an Einsatzgruppe firing squad. The Einsatzgruppen also targeted Jews throughout the occupied territories of Eastern Europe and the Soviet Union. By 1945, as many as 2 million civilians, including women, children, and the elderly (and at least half of them Jews), had been murdered by these mobile killing units. The Nazis hoped that the work of the Einsatzgruppen would lay the groundwork for the “Germanization” of Eastern Europe, which included the settlement of new German populations.