In the immediate postwar period, Mengele was in US custody. Unaware that Mengele's name already stood on a list of wanted war criminals, US officials quickly released him. From the summer of 1945 until spring 1949, using false papers, Mengele worked as a farmhand near Rosenheim, Bavaria. His prosperous family then aided his emigration to South America. He settled in Argentina.
Any remaining notes Mengele carried with him on his escape to South America and those were never found. Some forty years after the war, only a few of these twins could be found, many living in Israel and the United States. Strangely enough, many of them recall Mengele as a gentle, affable man who befriended them as children and gave them chocolates. Since many had immediately been separated from their families upon entering the camp, Mengele became a sort of father figure. Still a tension existed, that at any time they could be killed if they did not keep a low profile. Older twins recognized his kindness as a deception ...

Another Polish courier, Jan Karski, reached the west in November 1942, carrying messages from Jewish leaders in Poland. He had himself witnessed the conditions in the Warsaw ghetto and in what he believed to be the Belzec death camp, and was eager to inform the world. Karski saw the British foreign secretary, Anthony Eden, and US President Roosevelt, but they seemed to be more interested in military intelligence than in atrocity stories. Partly as a result of Karski's mission, however, the Allies agreed to a joint declaration, read to the British Parliament on 17 December, which acknowledged Nazi war crimes and threatened punishment for the perpetrators. Subsequently millions of leaflets were dropped in the course of bombing raids on German cities to inform Germans of the facts, but these had little or no effect.
Being a twin, regardless of age, meant survival in 1944. Some 3,000 children (or about 1,500 sets of twins) were selected for the experiments. They were not terrified of him but rather they were often intimidated by some of what he did. They knew of his temper and his passion for his work. Yet, they were also aware of his role in their survival. "Being on Mengele’s list was better than being on no list," said Eva Mozes Kor.
In 1942, Auschwitz II (Birkenau), originally intended to house slave laborers, began to be used instead as a combined labor camp and extermination camp.[23][24] Prisoners were transported there by rail from all over German-occupied Europe, arriving in daily convoys.[25] By July 1942, SS doctors were conducting "selections" where incoming Jews were segregated, and those considered able to work were admitted into the camp while those deemed unfit for labor were immediately killed in the gas chambers.[26] The arrivals that were selected to die, about three-quarters of the total,[a] included almost all children, women with small children, pregnant women, all the elderly, and all of those who appeared (in a brief and superficial inspection by an SS doctor) to be not completely fit and healthy.[28][29]
For the first time, camps were created specifically for Jews. Their conditions were far worse than other camps. The implicit intention was that the inmates would die there. Increasing numbers of Jews in Poland were relocated in ghettos. Non-Jewish Poles were also deported from their farms and villages to make room for ‘pure’ ethnic Germans to populate the new territory.
From the earliest years of the Nazi regime, German authorities persecuted homosexuals and others whose behavior did not match prescribed social norms. German police officials targeted thousands of political opponents (including Communists, Socialists, and trade unionists) and religious dissidents (such as Jehovah's Witnesses). Many of these individuals died as a result of incarceration and maltreatment.

As reported in The New York Times in 2015, "When Otto Frank first published his daughter's red-checked diary and notebooks, he wrote a prologue assuring readers that the book mostly contained her words".[53] Although many Holocaust deniers, such as Robert Faurisson, have claimed that Anne Frank's diary was fabricated,[54][55] critical and forensic studies of the text and the original manuscript have supported its authenticity.[56]
Jewish refugees were the subject of two international conferences, at Evian in 1938 and Bermuda in 1943. Neither conference resulted in any concrete action. In general, Britain treated refugees from Nazi Germany as economic migrants, and took in only those who would be of economic benefit to the country. About 10,000 Jewish children were brought to Britain in 1939 under the Kindertransport scheme, and placed with British families, but their parents were excluded and had to pay for their children's support. The best that can be said for Britain's refugee policy is that it was less ungenerous than that of most other European states at the time.
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]