The positions of physicists towards the NS-regime featured the full range of conducts and experiences: refugees, collaborators, resistance, followers, survivors. However, with the discovery of nuclear fission and the subsequent efforts to utilize the enormous released energies the physicists left normalcy and be came major players in the further development of World War II. During the first part of the course we will study these historical changes through the biographies of the participants. The war ended with the atomic bombs over the Japanese cities Hiroshima and Nagasaki in August 1945. In the second part of the course we will look at how the professional memory of the recent past was constructed. How did physicists see their responsibility and what were the actions that were taken? Which differences became acute during the Cold War and how were they related to the events in the past?