 Forty years later, the Nazis used another insecticide, Zyklon B, on civilians, including many Jews, in the gas chambers of Auschwitz and Majdanek during the Holocaust.The insecticide factory in Döbling was designed by the architect Hugo von Wiedenfeld and constructed by Karl Mayreder in 1888–1892.Explicitly oriental in style, the polychromed brick building with pointed arches, two minarets and a dome was one of Vienna's most recognized structures.