Though most Nazi concentration and extermination camps were destroyed after the war, some of them were turned into permanent memorials, and museums. In Communist Poland, some camps such as Majdanek, Jaworzno, Potulice and Zgoda were used by the Soviet NKVD to hold German prisoners of war, suspected or confirmed Nazis and Nazi collaborators, anti-Communists and other political prisoners, as well as civilian members of the German-speaking, Silesian and Ukrainian ethnic minorities. Currently, there are memorials to the victims of both Nazi and communist camps at Potulice; they have helped to enable a German-Polish discussion on historical perceptions of World War II. In East Germany, the concentration camps at Buchenwald and Sachsenhausen were used for similar purposes. Dachau concentration camp was used as a detention centre for the arrested Nazis.