While there were only 23 main camps between 1933 to 1945, the Nazi regime established some 20,000 other camps used for forced labor, transit or temporary internment. During the Holocaust it is estimated that 6 million Jews were slaughtered along with, 3 million Soviet prisoners of war, 3 million Polish Catholics, 700,000 Serbians, 250,000 Gypsies, Sinti, and Lalleri, 80,000 Germans (for political reasons), 70,000 German handicapped, 12,000 homosexuals, and 2,500 Jehovah’s Witnesses.
^ Ronald J. Berger (2002). Fathoming the Holocaust: A Social Problems Approach. Transaction Publishers. p. 57–8. ISBN 0202366111. Bureaucrats in the Reichsbahn performed important functions that facilitated the movement of trains. They constructed and published timetables, collected fares, and allocated cars and locomotives. In sending Jews to their death, they did not deviate much from the routine procedures they used to process ordinary train traffic.
When Menachem Begin came to power in 1977, he wanted a change. He made that clear in an early meeting with Yitzhak Hofi, who was then the director of the Mossad. “When Begin came in, he thought that not enough was being done and that there was a need to go on hunting Nazis,” Hofi later said in a classified interview with the Menachem Begin Heritage Center. “I told him, ‘Prime minister, today the Mossad has other missions that concern the national security of the people of Israel today and tomorrow, and I give preference to today and tomorrow over yesterday.’ ” Begin didn’t appreciate that response. “In the end we decided that we would focus on one more target, Mengele, but Begin, who was a very emotional man, was disappointed,” Hofi said.
In early 1942 the Nazis built killing centres at Treblinka, Sobibor, and Belzec in occupied Poland. The death camps were to be the essential instrument of the “final solution.” The Einsatzgruppen had traveled to kill their victims. With the killing centres, the process was reversed. The victims were taken by train, often in cattle cars, to their killers. The extermination camps became factories producing corpses, effectively and efficiently, at minimal physical and psychological cost to German personnel. Assisted by Ukrainian and Latvian collaborators and prisoners of war, a few Germans could kill tens of thousands of prisoners each month. At Chelmno, the first of the extermination camps, the Nazis used mobile gas vans. Elsewhere they built permanent gas chambers linked to the crematoria where bodies were burned. Carbon monoxide was the gas of choice at most camps. Zyklon-B, an especially lethal killing agent, was employed primarily at Auschwitz and later at Majdanek.
In 1935, Mengele earned a PhD in anthropology from the University of Munich. In January 1937, he joined the Institute for Hereditary Biology and Racial Hygiene in Frankfurt, where he worked for Dr. Otmar Freiherr von Verschuer, a German geneticist with a particular interest in researching twins. As von Verschuer's assistant, Mengele focused on the genetic factors that result in a cleft lip and palate, or a cleft chin. His thesis on the subject earned him a cum laude doctorate in medicine (MD) from the University of Frankfurt in 1938. (Both of his degrees were revoked by the issuing universities in the 1960s.) In a letter of recommendation, von Verschuer praised Mengele's reliability and his ability to verbally present complex material in a clear manner. The American author Robert Jay Lifton notes that Mengele's published works were in keeping with the scientific mainstream of the time, and would probably have been viewed as valid scientific efforts even outside Nazi Germany.