Timothy Snyder writes that Longerich "grants the significance of Greiser's murder of Jews by gas at Chełmno in December 1941", but also detects a significant moment of escalation in spring 1942, which includes "the construction of the large death factory at Treblinka for the destruction of the Warsaw Jews, and the addition of a gas chamber to the concentration camp at Auschwitz for the murder of the Jews of Silesia".[117] Longerich suggests that it "was only in the summer of 1942, that mass killing was finally understood as the realization of the Final Solution, rather than as an extensively violent preliminary to some later program of slave labor and deportation to the lands of a conquered USSR". For Longerich, to see mass killing as the Final Solution was an acknowledgement by the Nazi leadership that there would not be a German military victory over the USSR in the near future.[117]
Every day, twins were selected for experimentation. He would require that they give blood and sometimes so much was drawn that a twin would faint. Some underwent huge blood transfusions from one twin to the other. In an attempt to change their eye color, he painfully injected chemicals into their eyes, only to result in infection. One night he collected 7 sets of twins with different colored eyes, killed them, dissected them, and then sent the eyes to von Verschuer for analysis. Twins as young as 5 were killed from experiments, then their bodies dissected. For one pair of twins, he attempted to create conjoined twins by sewing their backs together and trying to connect blood vessels and organs. A few days after the extremely painful process, the twins developed gangrene and died. Many twins had their limbs and organs removed without the use of an anesthetic. Other experiments included isolation endurance, reactions to various stimuli, spinal taps without anesthesia, the removal of sexual organs, and incestuous impregnations. Out of the 1500 twins experimented on by Mengele, only around 200 survived the horror.

Uprisings broke out in some extermination camps. The few remaining Jews kept alive to dispose of bodies and sort possessions realised the number of transportees was reducing and they would be next. Civilian uprisings occurred across Poland as mainly young Jews, whose families had already been murdered, began to resist Nazi oppression. With reports of rebellion and mass murder in the British press, the situation in the camps could no longer be be ignored.

On 15 September 1935, the Reichstag passed the Reich Citizenship Law and the Law for the Protection of German Blood and German Honor, known as the Nuremberg Laws. The former said that only those of "German or kindred blood" could be citizens. Anyone with three or more Jewish grandparents was classified as a Jew.[107] The second law said: "Marriages between Jews and subjects of the state of German or related blood are forbidden." Sexual relationships between them were also criminalized; Jews were not allowed to employ German women under the age of 45 in their homes.[108] The laws referred to Jews but applied equally to the Roma and black Germans.[107]
Otto Frank later described what it was like when the Nazis entered the annex in which he had been hiding. He said an SS man picked up a portfolio and asked whether there were any jewels in it. When Otto Frank said it only contained papers, the SS man threw the papers (and Anne Frank’s diary) on the floor, walking away with silverware and a candlestick in his briefcase. “If he had taken the diary with him,” Otto Frank recalled, “no one would ever have heard of my daughter.”
The diary is not written in the classic forms of "Dear Diary" or as letters to oneself; Anne calls her diary "Kitty", so almost all of the letters are written to Kitty. Anne used the above-mentioned names for her annex-mates in the first volume, from September 25, 1942 until November 13, 1942, when the first notebook ends.[18] It is believed that these names were taken from characters found in a series of popular Dutch books written by Cissy van Marxveldt.[18]

His grip on German society tightened and those who publicly objected to Nazi policies were often sentenced to hard labour in the rapidly expanding concentration camp system. Jews were subjected to further laws restricting their rights, but rising anti-Semitism in Europe wasn’t limited to Germany. In the UK, Oswald Mosley’s British Union of Fascists gained support from sections of the public and press, even filling the Royal Albert Hall in April.

On September 21, 1939, Reinhard Heydrich ordered the establishment of the Judenräte (“Jewish Councils”), comprising up to 24 men—rabbis and Jewish leaders. Heydrich’s order made these councils personally responsible in “the literal sense of the term” for carrying out German orders. When the Nazis sealed the Warsaw Ghetto, the largest of German-occupied Poland’s 400 ghettos, in the fall of 1940, the Jews—then 30 percent of Warsaw’s population—were forced into 2.4 percent of the city’s area. The ghetto’s population reached a density of more than 200,000 persons per square mile (77,000 per square km) and 9.2 per room. Disease, malnutrition, hunger, and poverty took their toll even before the first bullet was fired.

The Nazis regarded the Slavs as subhuman, or Untermenschen.[426] In a secret memorandum dated 25 May 1940, Himmler stated that it was in German interests to foster divisions between the ethnic groups in the East. He wanted to restrict non-Germans in the conquered territories to schools that would only teach them how to write their own name, count up to 500, and obey Germans.[427][y] In November 1939 German planners called for "the complete destruction" of all Poles[430] and resettlement of the land by German colonists.[431] The Polish political leadership was the target of a campaign of murder (Intelligenzaktion and AB-Aktion).[432] Between 1.8 and 1.9 million non-Jewish Polish citizens perished at German hands during the course of the war; about four-fifths were ethnic Poles and the rest Ukrainians and Belarusians.[410] At least 200,000 died in concentration camps, around 146,000 in Auschwitz. Others died in massacres or in uprisings such as the Warsaw Uprising, where 120,000–200,000 were killed.[433] During the occupation, the Germans adopted a policy of restricting food and medical services, as well as degrading sanitation and public hygiene.[434] The death rate rose from 13 per 1000 before the war to 18 per 1000 during the war.[435] Around 6 million of World War II victims were Polish citizens; half the death toll were Jews.[436] Over the course of the war Poland lost 20 percent of its pre-war population.[436] Over 90 percent of the death toll came through non-military losses, through various deliberate actions by Germany and the Soviet Union.[433] Polish children were also kidnapped by Germans to be "Germanized", with perhaps as many as 200,000 children stolen from their families.[437]

“There is no stopping them [the Jews]. Are there no clear signs that the twilight of the Jews is setting in? No. Jewry’s control of society and politics as well as its domination of religious and ecclesiastical thought is still in the prime of its development. Yes, through the Jewish nation Germany will become a world power, a western new Palestine. And this will happen not through violent revolution but through the compliance of the people. We should not reproach the Jewish nation. It fought against the western world for 1,800 years and finally conquered it. We were vanquished. The Jews were late in their assault on Germany but once started there was no stopping them
Usage Note: Holocaust has a secure place in the language when it refers to the massive destruction of humans by other humans. In our 1987 survey 99 percent of the Usage Panel accepted the use of holocaust in the phrase nuclear holocaust. Sixty percent accepted the sentence As many as two million people may have died in the holocaust that followed the Khmer Rouge takeover in Cambodia. But because of its associations with genocide, people may object to extended applications of holocaust. The percentage of the Panel's acceptance drops sharply when people use the word to refer to death brought about by natural causes. In our 1999 survey 47 percent approved the sentence In East Africa five years of drought have brought about a holocaust in which millions have died. Just 16 percent approved The press gives little coverage to the holocaust of malaria that goes on, year after year, in tropical countries, where there is no mention of widespread mortality. The Panel has little enthusiasm for more figurative usages of holocaust. In 1999, only 7 percent accepted Numerous small investors lost their stakes in the holocaust that followed the precipitous drop in stocks. This suggests that these extended uses of the word may be viewed as overblown or in poor taste.
In the early 1990's, Argentine authorities opened its archives to reveal that several Nazi war criminals found safe haven in South America, including Dr. Josef Mengele, also known as Auschwitz’s Angel of Death. Mengele is infamous for his horrific experiments on inmates at the concentration camp. According to The New York Times in 1992, Mengele entered Argentina using a Red Cross-issued passport in 1949 and “practiced medicine in Buenos Aires for several years in the 1950s,” specializing in illegal abortions.
On June 6, 1944, also known as D-Day, more than 150,000 Allied soldiers landed in France. In December the Germans started an unsuccessful counterattack in Belgium and northern France, known as the Battle of the Bulge. Continuing to gain momentum, the Soviets began an offensive in January 1945, liberating western Poland and then forcing Hungary to surrender.
Höss oversaw the rapid construction of a gigantic new annex called Birkenau containing four large gas chamber-crematory buildings and scores of huts for slave laborers. From the moment it became operational in the spring of 1943, Auschwitz-Birkenau served as the focal point of the Nazi effort to exterminate the Jews. Hour after hour, trainloads of Jews arrived from all over Europe. The people were subjected to a life-and-death selection process by SS medical personnel such as Dr. Josef Mengele. Adults who seemed fit for labor were allowed to live and were marched away. All others, including children, the elderly and anyone deemed unfit went straight to the gas chambers.

Wounded while on campaign, Mengele returned to Germany in January 1943. He began work at the Kaiser Wilhelm Institute (KWI) for Anthropology, Human Genetics, and Eugenics, directed by his former mentor von Verschuer. In April of 1943, he received a promotion to the rank of SS captain. This promotion shortly preceded Mengele's transfer to Auschwitz, on May 30, 1943.

As the tide of World War II turned against the Nazis, they began a systematic plan to eliminate or "liquidate" the ghettos they had established, by a combination of mass murder on the spot and transferring the remaining residents to extermination camps. When the Nazis attempted to liquidate the Warsaw Ghetto on April 13, 1943, the remaining Jews fought back in what has become known as the Warsaw Ghetto Uprising. The Jewish resistance fighters held out against the entire Nazi regime for 28 days, longer than many European countries had been able to withstand Nazi conquest.
In response to a typhus epidemic in the women's camp, Mengele cleared one block of six hundred Jewish women and sent them to their deaths in the gas chambers. The building was then cleaned and disinfected, and the occupants of a neighboring block were bathed, de-loused, and given new clothing before being moved into the clean block. This process was repeated until all of the barracks were disinfected. Similar procedures were used for later epidemics of scarlet fever and other diseases, with infected prisoners being killed in the gas chambers. For these actions, Mengele was awarded the War Merit Cross (Second Class with swords) and was promoted in 1944 to First Physician of the Birkenau subcamp.[37]