When Hitler and his Nazis built the Warsaw Ghetto and herded 500,000 Polish Jews behind its walls to await liquidation, many Polish gentiles turned their backs or applauded. Not Irena Sendler. An unfamiliar name to most people, but this remarkable woman defied the Nazis and saved 2,500 Jewish children by smuggling them out of the Warsaw Ghetto. As a health worker, she sneaked the children out between 1942 and 1943 to safe hiding places and found non-Jewish families to adopt them.

The next year, 1942, marked the beginning of mass murder on a scale unprecedented in all of human history. In January, fifteen top Nazis led by Reinhard Heydrich, second in command of the SS, convened the Wannsee Conference in Berlin to coordinate plans for the Final Solution. The Jews of Europe would now be rounded up and deported into occupied Poland where new extermination centers were being constructed at Belzec, Sobibor, Treblinka, and Auschwitz-Birkenau.
In the German parliament, the Nazi party, led by Adolf Hitler, gained popularity. The number of seats Nazis controlled in the parliament rose from 12 in 1928 to 230 in 1932, making them the largest political party. The strong showing guaranteed the Nazi party would need to be part of any political coalition. Believing he could check Hitler’s ambition, President Hindenburg reluctantly made Hitler the Chancellor of Germany on January 30, 1933.
At the same time, the Germans set about liquidating the ghettos in occupied Poland. July 22, 1942, when the deportation of Jews from Warsaw to the death camp in Treblinka began, is regarded as a symbolic date. A decided majority of the Polish Jews were killed in a little over half a year, after which the SS began liquidating the Aktion Reinhard camps. However, the last great death camp—Auschwitz—remained in existence until the beginning of 1945. It was mainly Jews from Western and Southern Europe, from the liquidated labor camps, and the ghettos in Sosnowiec and Łódź, who died in the gas chambers there.
Today it seems that Nazi war criminals escaped to Argentina using false identities supplied by the Red Cross, the humanitarian organisation has admitted ...  The International Committee of the Red Cross has said it unwittingly provided travel papers to at least 10 top Nazis, including Adolf Eichmann, Klaus Barbie, Erich Priebke and Josef Mengele ... A statement issued by the ICRC, from its Geneva headquarters, said they were among thousands of people found in refugee camps who were given Red Cross travel documents.

Klempner, Mark (2017). "Heart Has Reasons: Holocaust Rescuers and Their Stories of Courage" (Website portal of resources for the book and lectures of the same name, with PDF and audio excerpts). hearthasreasons.com. The site includes extensive lists of articles, books and film/video/DVDs about Holocaust rescuers and related heroes, plus a reading group guide and book excerpts such as:

The Jews killed represented around one third of the world population of Jews,[398] and about two-thirds of European Jewry, based on an estimate of 9.7 million Jews in Europe at the start of the war.[399] Much of the uncertainty stems from the lack of a reliable figure for the number of Jews in Europe in 1939, numerous border changes that make avoiding double-counting of victims difficult, lack of accurate records from the perpetrators, and uncertainty about whether deaths occurring months after liberation, but caused by the persecution, should be counted.[392]
Further trials at Nuremberg took place between 1946 and 1949, which tried another 185 defendants.[460] West Germany initially tried few ex-Nazis, but after the 1958 Ulm Einsatzkommando trial, the government set up a governmental agency to investigate crimes.[461] Other trials of Nazis and collaborators took place in Western and Eastern Europe. In 1960, Mossad agents captured Adolf Eichmann in Argentina and brought him to Israel to stand trial on 15 indictments, including war crimes, crimes against humanity, and crimes against the Jewish people. He was convicted in December 1961 and executed in June 1962. Eichmann's trial and death revived interest in war criminals and the Holocaust in general.[462]

The Nazis brought their own strain of radical ruthlessness to these ideas. They glorified war and saw the uncompromising struggle for survival between nations and races as the engine of human progress. They rejected morality as a Jewish idea, which had corrupted and weakened the German people. They maintained that a great nation such as Germany had the right and duty to build an empire based on the subjugation of 'inferior races'. They looked eastwards to Poland and Russia (where, as it happened, the great majority of European Jews lived) for the territorial expansion of their 'living space' (Lebensraum).
These evacuations were regarded as provisional or "temporary solutions" ("Ausweichmöglichkeiten").[266][p] The final solution would encompass the 11 million Jews living not only in territories controlled by Germany, but elsewhere in Europe and adjacent territories, such as Britain, Ireland, Switzerland, Turkey, Sweden, Portugal, Spain, and Hungary, "dependent on military developments".[266] There was little doubt what the final solution was, writes Peter Longerich: "the Jews were to be annihilated by a combination of forced labour and mass murder".[268]
In 1950, the Dutch translator Rosey E. Pool made a first translation of the Diary, which was never published.[26] At the end of 1950, another translator was found to produce an English-language version. Barbara Mooyaart-Doubleday was contracted by Vallentine Mitchell in England, and by the end of the following year, her translation was submitted, now including the deleted passages at Otto Frank's request. As well, Judith Jones, while working for the publisher Doubleday, read and recommended the Diary, pulling it out of the rejection pile.[27] Jones recalled that she came across Frank's work in a slush pile of material that had been rejected by other publishers; she was struck by a photograph of the girl on the cover of an advance copy of the French edition. "I read it all day", she noted. "When my boss returned, I told him, 'We have to publish this book.' He said, 'What? That book by that kid?'" She brought the diary to the attention of Doubleday's New York office. "I made the book quite important because I was so taken with it, and I felt it would have a real market in America. It's one of those seminal books that will never be forgotten", Jones said.[28] The book appeared in the United States and in the United Kingdom in 1952, becoming a best-seller. The introduction to the English publication was written by Eleanor Roosevelt.
The most notorious physician was Josef Mengele, an SS officer who became the Auschwitz camp doctor on 30 May 1943.[54] Interested in genetics[54] and keen to experiment on twins, he would pick out subjects from the new arrivals during "selection" on the ramp, shouting "Zwillinge heraus!" (twins step forward!).[55] They would be measured, killed, and dissected. One of Mengele's assistants said in 1946 that he was told to send organs of interest to the directors of the "Anthropological Institute in Berlin-Dahlem". This is thought to refer to Mengele's academic supervisor, Otmar Freiherr von Verschuer , director from October 1942 of the Kaiser Wilhelm Institute of Anthropology, Human Heredity, and Eugenics in Berlin-Dahlem.[56][55][i] Mengele's experiments included placing subjects in pressure chambers, testing drugs on them, freezing them, attempting to change their eye color by injecting chemicals into children's eyes, and amputations and other surgeries.[59]
The Protocol also highlighted the fact that in Slovakia, Croatia and Romania, local governments were working with the Nazis in their anti-Jewish activities. In Italy, the Nazis planned to liaise with the Italian police. France, the document said, would not prove difficult. It was noted that there was much opposition to the Nazis’ anti-Jewish policies in the Nordic States, and that the ‘Final Solution’ would be postponed for a while in these countries.
Of the eight people in the secret annex, only Otto Frank survived the war. He subsequently returned to Amsterdam, where Gies gave him various documents she had saved from the annex. Among the papers was Anne’s diary, though some of the notebooks were missing, notably most of those from 1943. To fulfill Anne’s dream of publication, Otto began sorting through her writings. The original red-and-white checkered journal became known as the “A” version, while her revised entries, written on loose sheets of paper, were known as the “B” version. The diary that Otto ultimately compiled was the “C” version, which omitted approximately 30 percent of her entries. Much of the excluded text was sexual-related or concerned Anne’s difficulties with her mother.

Thus although the Nazi 'Final Solution' was one genocide among many, it had features that made it stand out from all the rest as well. Unlike all the others it was bounded neither by space nor by time. It was launched not against a local or regional obstacle, but at a world-enemy seen as operating on a global scale. It was bound to an even larger plan of racial reordering and reconstruction involving further genocidal killing on an almost unimaginable scale, aimed, however, at clearing the way in a particular region – Eastern Europe – for a further struggle against the Jews and those the Nazis regarded as their puppets. It was set in motion by ideologues who saw world history in racial terms. It was, in part, carried out by industrial methods. These things all make it unique.
There has been much conjecture about the identity or inspiration of Kitty, who in Anne's revised manuscript is the sole recipient of her letters. In 1996, the critic Sietse van der Hoek wrote that the name referred to Kitty Egyedi, a prewar friend of Anne's. Van der Hoek may have been informed by the publication A Tribute to Anne Frank (1970), prepared by the Anne Frank Foundation, which assumed a factual basis for the character in its preface by the then-chairman of the Foundation, Henri van Praag, and accentuated this with the inclusion of a group photograph that singles out Anne, Sanne Ledermann, Hanneli Goslar, and Kitty Egyedi. Anne does not mention Kitty Egyedi in any of her writings (in fact, the only other girl mentioned in her diary from the often reproduced photo, other than Goslar and Ledermann, is Mary Bos, whose drawings Anne dreamed about in 1944) and the only comparable example of Anne's writing unposted letters to a real friend are two farewell letters to Jacqueline van Maarsen, from September 1942.[20]

The survey of her manuscripts compared an unabridged transcription of Anne Frank's original notebooks with the entries she expanded and clarified on loose paper in a rewritten form and the final edit as it was prepared for the English translation. The investigation revealed that all of the entries in the published version were accurate transcriptions of manuscript entries in Anne Frank's handwriting, and that they represented approximately a third of the material collected for the initial publication. The magnitude of edits to the text is comparable to other historical diaries such as those of Katherine Mansfield, Anaïs Nin and Leo Tolstoy in that the authors revised their diaries after the initial draft, and the material was posthumously edited into a publishable manuscript by their respective executors, only to be superseded in later decades by unexpurgated editions prepared by scholars.[57]
On January 20, 1942, several top officials of the German government met to officially coordinate the military and civilian administrative branches of the Nazi system to organize a system of mass murder of the Jews. This meeting, called the Wannsee Conference, "marked the beinning of the full-scale, comprehensive extermination operation [of the Jews] and laid the foundations for its organization, which started immediately after the conference ended" (Yahil, The Holocaust, p. 318).
Despite the overwhelming odds, individual rescues sometimes succeeded, especially if the Jewish fugitives could pass as natives in language, manner, and appearance; if the hideout was skillfully camouflouged; if the local population was sympathetic; if geography and distance from neighboring homes aided concealment; and if organized groups or sympathetic friends provided additional safe houses and forged ration papers for essentials like food and clothing.
Hitler was obsessed with the idea of the superiority of the “pure” German race, which he called “Aryan,” and with the need for “Lebensraum,” or living space, for that race to expand. In the decade after he was released from prison, Hitler took advantage of the weakness of his rivals to enhance his party’s status and rise from obscurity to power. On January 30, 1933, he was named chancellor of Germany. After President Paul von Hindenburg’s death in 1934, Hitler anointed himself as “Fuhrer,” becoming Germany’s supreme ruler.
Unlike concentration camps, death camps had no barracks to house prisoners, other than those for workers at the camps. In order to process the murder of thousands of people, great pains were taken to deceive the victims concerning their fate. Jews deported from ghettos and concentration camps to the death camps were unaware of what they were facing. The Nazi planners of the operation told the victims that they were being resettled for labor, issued them work permits, told them to bring along their tools and to exchange their German marks for foreign currency. Food was also used to coax starving Jews onto the trains. Once the trains arrived at the death camps, trucks were available to transport those who were too weak to walk directly to the gas chambers. The others were told that they would have to be deloused and enter the baths. The victims were separated by sex and told to remove their clothes. The baths were in reality the gas chambers. The shower heads in the baths were actually the inlets for poison gas. At Auschwitz, the gas chambers held 2,000 people at a time. With the introduction of a cyanide-based gas called Zyklon B, all 2,000 occupants could be killed in five minutes. As a result of this technological “advancement,” Auschwitz was able to “process” the death of 12,000 victims daily. Before the bodies were removed by workers with gas masks and burned in crematoria, the teeth of the victims were stripped for gold, which was melted down and shipped back to Germany. Innocent victims were exploited and desecrated to a degree unknown in human history.
Before the war, Mengele had received doctorates in anthropology and medicine, and began a career as a researcher. He joined the Nazi Party in 1937 and the SS in 1938. He was assigned as a battalion medical officer at the start of World War II, then transferred to the Nazi concentration camps service in early 1943 and assigned to Auschwitz, where he saw the opportunity to conduct genetic research on human subjects. His subsequent experiments focused primarily on twins, with little regard for the health or safety of the victims.[2][3]