Olga Lengyel, a prisoner at the Birkenau camp, wrote in her book entitled "Five Chimneys" that she had heard about Dr. Mengele from the other inmates before she saw him. Lengyel wrote that she had heard that Dr. Mengele was "good-looking" but she was surprised by how "really handsome" he was. Lengyel wrote, regarding Dr. Mengele: "Though he was making decisions that meant extermination, he was as pleasantly smug as any man could be."
Dr. Mengele was nicknamed the "Angel of Death" by the prisoners because he had the face of an angel, yet he callously made selections for the gas chambers at Birkenau. He was nice to the children in the camp, yet he experimented on them as though they were laboratory rats. He volunteered to do the selections at Birkenau, even when it wasn't his turn, because he wanted to find subjects for his medical research on genetic conditions and hereditary diseases, which he had already begun before the war. He particularly wanted to find twins for the research that he had started before he was posted to Birkenau.
It is not known when Hitler formed the intention of the “final solution of the Jewish question” on the scale of the European continent. The conference in Wannsee on January 20, 1942 considered only the details of the undertaking: the methods for organizing the deportation and ensuring the cooperation of the civilian administration. Overall, the plans called for the murder of 11 million Jews living in Germany, the occupied territory, the states opposed to the Third Reich, and the allied and neutral countries. 
Because of this book, we will remember the names, the quirks -- the characters -- of the eight people who inhabited the secret annex and their brave Dutch helpers. We will be able to visualize them long after everyone who witnessed that horrific era is gone. It is because of Anne's diary that she and her family are among the few we will remember -- the ones we feel we know -- among the millions who suffered and died as she did.
The ideology of Nazism brought together elements of antisemitism, racial hygiene, and eugenics, and combined them with pan-Germanism and territorial expansionism with the goal of obtaining more Lebensraum (living space) for the Germanic people.[16] Nazi Germany attempted to obtain this new territory by attacking Poland and the Soviet Union, intending to deport or kill the Jews and Slavs living there, who were considered by the Nazis to be inferior to the Aryan master race.[17]