As a temporary measure, while the top leadership considered long-term options, German authorities established ghettos in the Generalgouvernement (that part of German-occupied Poland not directly annexed to Germany, attached to German East Prussia or incorporated into the German-occupied Soviet Union) and in the District Wartheland, commonly called the Warthegau (an area of western Poland directly annexed to the German Reich). From late 1939, German SS and police authorities deported Polish, German, Austrian, and Czech Jews to these ghettos.
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.”
There was "practically no resistance" in the ghettos in Poland by the end of 1942, according to Peter Longerich.[305] Raul Hilberg accounted for this by evoking the history of Jewish persecution: as had been the case before, appealing to their oppressors and complying with orders might avoid inflaming the situation until the onslaught abated.[306] Henri Michel argued that resistance consisted not only of physical opposition but of any activity that gave the Jews humanity in inhumane conditions, while Yehuda Bauer defined resistance as actions that in any way opposed the German directives, laws, or conduct.[307] Hilberg cautioned against overstating the extent of Jewish resistance, arguing that turning isolated incidents into resistance elevates the slaughter of innocent people into some kind of battle, diminishes the heroism of those who took active measures to resist, and deflects questions about the survival strategies and leadership of the Jewish community.[308] Timothy Snyder noted that it was only during the three months after the deportations of July–September 1942 that agreement on the need for armed resistance was reached.[309]
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.
SS-Obergruppenführer Reinhard Heydrich, head of the Reich Main Security Office (Reichssicherheitshauptamt or RSHA), convened what became known as the Wannsee Conference on 20 January 1942 at Am Großen Wannsee 56–58, a villa in Berlin's Wannsee suburb.[256][257] The meeting had been scheduled for 9 December 1941, and invitations had been sent on 29 November, but it had been postponed.[258]
The Nazis, under cover of the war, developed the technology, bureaucracy, and psychology of hate to efficiently murder millions of Jews. The details of the “Final Solution” were worked out at the Wannsee Conference. All Jews in Germany and the occupied countries were deported to sealed ghettos as a holding area. Many were then shipped in cattle cars to labor camps where they lived under brutally inhuman conditions. Hundreds of thousands were sent directly to the gas chambers in death camps. As the Allies advanced on the camps, death marches further depleted the ranks of potential camp survivors.
Beginning in late 1941, the Germans began mass transports from the ghettoes in Poland to the concentration camps, starting with those people viewed as the least useful: the sick, old and weak and the very young. The first mass gassings began at the camp of Belzec, near Lublin, on March 17, 1942. Five more mass killing centers were built at camps in occupied Poland, including Chelmno, Sobibor, Treblinka, Majdanek and the largest of all, Auschwitz-Birkenau. From 1942 to 1945, Jews were deported to the camps from all over Europe, including German-controlled territory as well as those countries allied with Germany. The heaviest deportations took place during the summer and fall of 1942, when more than 300,000 people were deported from the Warsaw ghetto alone.
Under the Nuremberg Laws, Jews became routine targets for stigmatization and persecution. This culminated in Kristallnacht, or the “night of broken glass” in November 1938, when German synagogues were burned and windows in Jewish shops were smashed; some 100 Jews were killed and thousands more arrested. From 1933 to 1939, hundreds of thousands of Jews who were able to leave Germany did, while those who remained lived in a constant state of uncertainty and fear.
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."

Josef Mengele (/ˈmɛŋɡələ/; German: [ˈmɛŋələ]; 16 March 1911 – 7 February 1979) was a German Schutzstaffel (SS) officer and physician in Auschwitz concentration camp during World War II. He performed deadly human experiments on prisoners and was a member of the team of doctors who selected victims to be killed in the gas chambers. Arrivals that were judged able to work were admitted into the camp, while those deemed unsuitable for labor were sent to the gas chambers to be killed. With Red Army troops sweeping through Poland, Mengele was transferred 280 kilometers (170 mi) from Auschwitz to the Gross-Rosen concentration camp on 17 January 1945, just ten days before the arrival of the Soviet forces at Auschwitz. After the war, he fled to South America where he evaded capture for the rest of his life.