Around 50,000 German gay men were jailed between 1933 and 1945, and 5,000–15,000 are estimated to have been sent to concentration camps. It is not known how many died during the Holocaust. James Steakley writes that what mattered in Germany was criminal intent or character, rather than acts, and the "gesundes Volksempfinden" ("healthy sensibility of the people") became the guiding legal principle. In 1936, Himmler created the Reich Central Office for the Combating of Homosexuality and Abortion. The Gestapo raided gay bars, tracked individuals using the address books of those they arrested, used the subscription lists of gay magazines to find others, and encouraged people to report suspected homosexual behavior and to scrutinize the behavior of their neighbors. Lesbians were left relatively unaffected; the Nazis saw them as "asocials", rather than sexual deviants. Gay men convicted between 1933 and 1944 were sent to camps for "rehabilitation", where they were identified by pink triangles. Hundreds were castrated, sometimes "voluntarily" to avoid criminal sentences. Steakley writes that the full extent of gay suffering was slow to emerge after the war. Many victims kept their stories to themselves because homosexuality remained criminalized in postwar Germany.
Ellis, as well as Zaloga in his study of the Polish Campaign in 1939, points to the effective use of other arms such as artillery and aerial firepower as equally important to the success of German (and later, Allied) operations. Panzer operations in Russia failed to provide decisive results; Leningrad never fell despite an entire Panzer Group being assigned to take it, nor did Moscow. In 1942 panzer formations overstretched at Stalingrad and in the Caucasus, and what successes did take place - such as Manstein at Kharkov or Krivoi Rog - were of local significance only.
Höss was succeeded as Auschwitz commandant in November 1943 by SS Obersturmbannführer Arthur Liebehenschel, who served until 15 May 1944. SS Sturmbannführer Richard Baer became commandant of Auschwitz I on 11 May 1944, and SS Obersturmbannführer Fritz Hartjenstein of Auschwitz II from 22 November 1943, followed by SS Obersturmbannführer Josef Kramer from 15 May 1944 until the camp's liquidation in January 1945. Heinrich Schwarz was commandant of Auschwitz III from the point at which it became an autonomous camp in November 1943 until its liquidation.
The gas chambers worked to their fullest capacity from April to July 1944, during the massacre of Hungary's Jews. Hungary was an ally of Germany during the war, but it had resisted turning over its Jews until Germany invaded that March. A rail spur leading to crematoria II and III in Auschwitz II was completed that May, and a new ramp was built between sectors BI and BII to deliver the victims closer to the gas chambers. On 29 April the first 1,800 Hungarian Jews arrived at the camp; from 14 May until early July 1944, 437,000 Hungarian Jews, half the pre-war population, were deported to Auschwitz, at a rate of 12,000 a day for a considerable part of that period. The crematoria had to be overhauled. Crematoria II and III were given new elevators leading from the stoves to the gas chambers, new grates were fitted, and several of the dressing rooms and gas chambers were painted. Cremation pits were dug behind crematorium V. The last mass transports to arrive in Auschwitz were 60,000–70,000 Jews from the Łódź Ghetto, some 2,000 from Theresienstadt, and 8,000 from Slovakia. The last selection took place on 30 October 1944. Crematorium IV was demolished after the Sonderkommando revolt on 7 October 1944. The SS blew up crematorium V on 14 January 1945, and crematoria II and III on 20 January.
Killing on a mass scale using gas chambers or gas vans was the main difference between the extermination and concentration camps. From the end of 1941, the Germans built six extermination camps in occupied Poland: Auschwitz II-Birkenau, Majdanek, Chełmno, and the three Operation Reinhard camps at Belzec, Sobibor, and Treblinka II. Maly Trostenets, a concentration camp in the Reichskommissariat Ostland, became a killing centre in 1942. Gerlach writes that over three million Jews were murdered in 1942, the year that "marked the peak" of the mass murder of Jews. At least 1.4 million of these were in the General Government area of Poland.
The technique of Blitzkrieg is based on the principle of surprise as opposed to an effort to crush an enemy by bringing an overwhelming superiority in numbers and armament to bear against him. It can be likened to the swift and deadly thrust of a rapier as opposed to the crushing blow of a battle-axe or a war club. The objective is not the enemy civilian population but the enemy armed forces, both ground and air.
After Germany invaded Poland in September 1939, sparking World War II, the Germans converted Auschwitz I from an army barracks to hold Polish political prisoners. The first prisoners, German criminals brought to the camp as functionaries, arrived in May 1940, and the first gassing of prisoners took place in block 11 of Auschwitz I in September 1941. Auschwitz II–Birkenau went on to become a major site of the Nazis' Final Solution to the Jewish Question. From early 1942 until late 1944, transport trains delivered Jews from all over German-occupied Europe to the camp's gas chambers. Of the estimated 1.3 million people sent to Auschwitz, at least 1.1 million died, around 90 percent of them Jews. Approximately one in six Jews killed in the Holocaust died at the camp. Others deported to Auschwitz included 150,000 non-Jewish Poles, 23,000 Roma, 15,000 Soviet prisoners of war, 400 Jehovah's Witnesses, tens of thousands of others of diverse nationalities, and an unknown number of gay men. Many of those not killed in the gas chambers died because of starvation, forced labor, infectious diseases, individual executions, and medical experiments.
Those deported to Auschwitz arrived at the nearby train station and were marched or trucked to the main camp where they were registered, tattooed, undressed, deloused, had their body hair shaven off, showered while their clothes were disinfected with Zyklon-B gas, and entered the camp under the infamous gateway inscribed 'Arbeit Macht Frei' ("Labor make you free")
A comprehensively detailed work of definitive scholarship, "Blitzkrieg: From the Ground Up" by Niklas Zetterling (a military historian and researcher at the Swedish Defense College) is an examination of the German Blitzkrieg operations from Poland to Operation Barbarossa, as experienced by junior commanders and enlisted men, exploring why they were so successful.
In October 1939 Hitler signed a "euthanasia decree" backdated to 1 September 1939 that authorized Reichsleiter Philipp Bouhler, the chief of Hitler's Chancellery, and Karl Brandt, Hitler's personal physician, to carry out a program of involuntary "euthanasia"; after the war this program was named Aktion T4. It was named after Tiergartenstraße 4, the address of a villa in the Berlin borough of Tiergarten, where the various organizations involved were headquartered. T4 was mainly directed at adults, but the "euthanasia" of children was also carried out. Between 1939 and 1941, 80,000 to 100,000 mentally ill adults in institutions were killed, as were 5,000 children and 1,000 Jews, also in institutions. In addition there were specialized killing centres, where the deaths were estimated at 20,000, according to Georg Renno, the deputy director of Schloss Hartheim, one of the "euthanasia" centers, or 400,000, according to Frank Zeireis, the commandant of the Mauthausen concentration camp. Overall, the number of mentally and physically handicapped murdered was about 150,000.
Despite the term blitzkrieg being coined by journalists during the Invasion of Poland of 1939, historians Matthew Cooper and J. P. Harris have written that German operations during it were consistent with traditional methods. The Wehrmacht strategy was more in line with Vernichtungsgedanken a focus on envelopment to create pockets in broad-front annihilation. Panzer forces were dispersed among the three German concentrations with little emphasis on independent use, being used to create or destroy close pockets of Polish forces and seize operational-depth terrain in support of the largely un-motorized infantry which followed.
In 1939, shortly after the war began, the Germans initiated the T4 Program—framed euphemistically as a “euthanasia” program—for the murder of intellectually or physically disabled and emotionally disturbed Germans who by their very existence violated the Nazi ideal of Aryan supremacy. They were termed “life unworthy of life.” An economic justification was also employed as these Germans were considered “useless eaters.” The Nazis pioneered the use of gas chambers and mass crematoria under this program. The murder of the disabled was the training ground for key personnel who were to later staff the death camps of Aktion Reinhard. The German public protested these murders. The Roman Catholic bishop of Münster, Clemens August, Graf von Galen, preached against them, and the T4 program was formally halted. Nonetheless, the murder and sterilization of these German “Aryans” continued secretly throughout the war.
Advocacy organizations worldwide called for British Royal Air Forces to bomb concentration camps particularly at Auschwitz. Although the plan was adopted by British Prime Minister Winston Churchill poor information-sharing between parts of the British government led the order to be ignored and the plan dropped. Such calculations were hardly the low point of Allied Responses. One story has that, low on supplies, the Nazis offered the British a million Jews in exchange for 10,000 trucks, which one British diplomat promptly refused saying, “What would I do with one million Jews? Where would I put them?”
Schindler first arrived in Kraków in October 1939, on Abwehr business, and took an apartment the following month. Emilie maintained the apartment in Ostrava and visited Oskar in Kraków at least once a week. In November 1939, he contacted interior decorator Mila Pfefferberg to decorate his new apartment. Her son, Leopold "Poldek" Pfefferberg, soon became one of his contacts for black market trading. They eventually became lifelong friends.