When an Allied photo reconnaissance plane flew over southern Poland in the summer of 1944it took horrifying images of the Nazi’s most evil extermination camp, Auschwitz. The gas chambers and the crematoria in which 12,000 people were being murdered daily are clearly visible. But the photos were not analyzed at the time, simply filed away. Using these photos as a unique starting point, we take a new look at the Holocaust and ask what the Allies knew about the extermination camp and when they found out. When Churchill heard about Auschwitz, he implored the RAF to bomb it or the railway lines leading to it. But this was not done. We explore all the arguments around the practical difficulties of bombing Auschwitz, but the question remains whether the Allies should not have done something to stop the killing. Includes interviews with Auschwitz survivors and expert historians.