There have been many atrocities committed throughout history. The Holocaust was not the first or the last. Why is the Holocaust recalled with such horror?

The Holocaust, also known as the Shoah, was the World War II genocide of the European Jews. Between 1941 and 1945, across German-occupied Europe, Nazi Germany and its collaborators systematically murdered some six million Jews, around two-thirds of Europe's Jewish population

Explanation: The Allied powers were not particularly concerned with the destruction of the Death Camps because they thought that concentrating their attacks on German industrial capacity would weaken the Nazi regime much more effectively. (In other words, dropping bombs on Auschwitz would not have shortened the war by one day.) Whether or not this is true is contentious -- and it has been used to argue that the Allies were not morally superior.