The Holocaust, also known as the Shoah,[b] was a genocide during World War II in which Nazi Germany, aided by local collaborators, systematically murdered some six million European Jews—around two-thirds of the Jewish population of Europe—between 1941 and 1945.[a][c] Jews were targeted for extermination as part of a larger event during the Holocaust era, in which Germany and its collaborators persecuted and murdered other groups, including Slavs (chiefly ethnic Poles, Soviet prisoners of war, and Soviet citizens), the Roma, the "incurably sick", political and religious dissenters such as communists and Jehovah's Witnesses, and gay men.[d] Taking into account all the victims of Nazi persecution, the death toll rises to over 17 million.[3]
In the manuscript, her original diaries are written over three extant volumes. The first volume (the red-and-white checkered autograph book) covers the period between June 14 and December 5, 1942. Since the second surviving volume (a school exercise book) begins on December 22, 1943, and ends on April 17, 1944, it is assumed that the original volume or volumes between December 1942 and December 1943 were lost - presumably after the arrest, when the hiding place was emptied on Nazi instructions. However, this missing period is covered in the version Anne rewrote for preservation. The third existing volume (which was also a school exercise book) contains entries from April 17 to August 1, 1944, when Anne wrote for the last time before her arrest.[16]:2

Zeidel had spent the previous two years in German-occupied Vilnius, in the city’s walled-off Jewish ghetto. He’d watched as the Nazis sent first hundreds and then thousands of Jews by train or truck or on foot to a camp in the forest. A small number of people managed to flee the camp, and they returned with tales of what they’d seen: rows of men and women machine-gunned down at close range. Mothers pleading for the lives of their children. Deep earthen pits piled high with corpses. And a name: Ponar.

In his 1965 essay "Command and Compliance", which originated in his work as an expert witness for the prosecution at the Frankfurt Auschwitz Trials, the German historian Hans Buchheim wrote there was no coercion to murder Jews and others, and all who committed such actions did so out of free will. Buchheim wrote that chances to avoid executing criminal orders "were both more numerous and more real than those concerned are generally prepared to admit",[468] and that he found no evidence that SS men who refused to carry out criminal orders were sent to concentration camps or executed.[469] Moreover, SS rules prohibited acts of gratuitous sadism, as Himmler wished for his men to remain "decent"; acts of sadism were carried out on the initiative of those who were either especially cruel or wished to prove themselves ardent National Socialists.[468] Finally, he argued that those of a non-criminal bent who committed crimes did so because they wished to conform to the values of the group they had joined and were afraid of being branded "weak" by their colleagues if they refused.[470]
The Holocaust began in 1933 when Adolf Hitler came to power in Germany and ended in 1945 when the Nazis were defeated by the Allied powers. The term Holocaust is derived from the Greek word holokauston, which means sacrifice by fire. It refers to the Nazi persecution and planned slaughter of the Jewish people and others considered inferior to "true" Germans. The Hebrew word Shoah, which means devastation, ruin or waste, also refers to this genocide.
German forces had begun evacuating many of the death camps in the fall of 1944, sending inmates under guard to march further from the advancing enemy’s front line. These so-called “death marches” continued all the way up to the German surrender, resulting in the deaths of some 250,000 to 375,000 people. In his classic book “Survival in Auschwitz,” the Italian Jewish author Primo Levi described his own state of mind, as well as that of his fellow inmates in Auschwitz on the day before Soviet troops arrived at the camp in January 1945: “We lay in a world of death and phantoms. The last trace of civilization had vanished around and inside us. The work of bestial degradation, begun by the victorious Germans, had been carried to conclusion by the Germans in defeat.”
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]