Blitzkrieg   (German, literally lightning war or flash war) is a popular name for an offensive operational-level military doctrine which involves an initial bombardment followed by employment of mobile forces attacking with speed and surprise to prevent an enemy from implementing a coherent defense. The founding principles of these types of operations were developed in the 19th Century by various nations, and adapted in the years after World War I, largely by the German Wehrmacht, to incorporate modern weapons and vehicles as a method to help prevent trench warfare and linear warfare in future conflicts. The first practical implementations of these concepts coupled with modern technology were instituted by the Wehrmacht in the opening battles of World War II. While operations in Poland were rather conventional, subsequent battles — particularly the invasions of France, The Netherlands and initial operations in the Soviet Union — were effective owing to surprise penetrations, general enemy unpreparedness and an inability to react swiftly enough to German offensive operations. That the German Army quickly defeated numerically and technically superior enemies in France led many analysts to believe that a new system of warfare had been invented.
The Zyklon B was delivered by ambulance to the crematoria by a special SS bureau known as the Hygienic Institute.[104] The actual delivery of the gas to the victims was always handled by the SS, on the order of the supervising SS doctor.[173][174] After the doors were shut, SS men dumped in the Zyklon B pellets through vents in the roof or holes in the side of the chamber. The victims were dead within 20 minutes.[173] Despite the thick concrete walls, screaming and moaning from within could be heard outside. In one failed attempt to muffle the noise, two motorcycle engines were revved up to full throttle nearby, but the sound of yelling could still be heard over the engines.[175]
In the last months of Hitler’s Reich, as the German armies retreated, the Nazis began marching the prisoners still alive in the concentration camps to the territory they still controlled. The Germans forced the starving and sick Jews to walk hundreds of miles. Most died or were shot along the way. About a quarter of a million Jews died on the death marches.

"...(t)hroughout ( the Polish Campaign), the employment of the mechanized units revealed the idea that they were intended solely to ease the advance and to support the activities of the infantry....Thus, any strategic exploitation of the armored idea was still-born. The paralysis of command and the breakdown of morale were not made the ultimate aim of the ... German ground and air forces, and were only incidental by-products of the traditional maneuvers of rapid encirclement and of the supporting activities of the flying artillery of the Luftwaffe, both of which had has their purpose the physical destruction of the enemy troops. Such was the Vernichtungsgedanke of the Polish campaign."
You find gripping and horrifying stories of Adolf Hitler and his most ruthless henchmen - men often seen as the very personifications of evil, like Rudolf Hoess, the SS Commandant of Auschwitz, the Nazi butcher Amon Goeth at Plaszow and Josef Mengele, The Angel Of Death. You may read about Hitler's wife, Eva Braun, or Admiral Wilhelm Canaris, Chief of the German Military Intelligence who was a dedicated anti-Nazi and held Hitler in utter contempt. He tried to put a stop to the crimes of war and genocide committed by the Nazis.
In his 1983 book, Popular Opinion and Political Dissent in the Third Reich, Ian Kershaw examined the Alltagsgeschichte (history of everyday life) in Bavaria during the Nazi period. The most common viewpoint of Bavarians was indifference towards what was happening to the Jews, he wrote. Most Bavarians were vaguely aware of the genocide, but they were vastly more concerned about the war.[472] Kershaw argued that "the road to Auschwitz was built by hate, but paved with indifference".[473] His assessment faced criticism from historians Otto Dov Kulka and Michael Kater. Kater maintained that Kershaw had downplayed the extent of popular antisemitism. Although most of the "spontaneous" antisemitic actions of Nazi Germany had been staged, Kater argued that these had involved substantial numbers of Germans, and therefore it was wrong to view the extreme antisemitism of the Nazis as coming solely from above.[474] Kulka argued that "passive complicity" would be a better term than "indifference".[475] Focusing on the views of Germans opposed to the Nazi regime, the German historian Christof Dipper, in his essay "Der Deutsche Widerstand und die Juden" (1983), argued that the majority of the anti-Nazi national-conservatives were antisemitic. No one in the German resistance supported the Holocaust, but Dipper wrote that the national conservatives did not intend to restore civil rights to the Jews after the planned overthrow of Hitler.[474]

December 8, 1941 - In occupied Poland, near Lodz, Chelmno extermination camp becomes operational. Jews taken there are placed in mobile gas vans and driven to a burial place while carbon monoxide from the engine exhaust is fed into the sealed rear compartment, killing them. The first gassing victims include 5,000 Gypsies who had been deported from the Reich to Lodz.

^ These are some of the many notable historians that have casually used the term blitzkrieg—including some who have written on its misconception—to describe several Wehrmacht military operations that were spearheaded by a dense concentration of armoured and motorised formations with the aim of delivering a breakthrough, and exploiting it with speed to paralyse and encircle the enemy: David Glantz (Glantz 2010, p. 14; Glantz 2009, p. 164; Glantz 2001), Jonathan House (Glantz & House 1999, pp. 254, 269; Glantz & House 1995, pp. 61, 125, 167, 226, 274, 286, 288), Lloyd Clark (Clark 2012, pp. 22–27, 187), Antony Beevor (Beevor 1999, pp. 13, 148; Beevor 2006, p. 157), Mungo Melvin (Melvin 2011, pp. 46, 79–80, 199), John Erickson (Erickson 2001, pp. 558, 567) and Steven Mercatante (Mercatante 2012, pp. 65, 77, 91, 301).
The brick barracks were constructed in the autumn of 1941. The Germans originally intended the barracks to house 40 prisoners, but very often more than 700 would be placed in each of them. The total number of prisoners to each barrack depended on the number of transports arriving. The prisoners slept in 60 spaces, with three bunks in each space. Prisoners slept on straw spread over the wooden bunks. The barracks had earth floors and few sanitary facilities.
He began by turning his factory into an official subcamp of a newly constructed labor camp at Plazów. For a time, it was a haven for about 500 Jews. Then, in the fall of 1944, the Nazis ordered both camps closed and all workers shipped to Auschwitz, a killing center. Schindler refused to let that happen. He put together a list of 1,100 men, women, and children that he claimed as his workers. He then used his money and influence to transport those workers to a new factory he was building at Brinnlitz, Czechoslovakia. When the Jewish women who worked in his factory were transported to Auschwitz by mistake, he accomplished the impossible: he managed to get the women back by offering Nazi officials a fortune in bribes.
Oskar Schindler (28 April 1908 – 9 October 1974) was a German industrialist and a member of the Nazi Party who is credited with saving the lives of 1,200 Jews during the Holocaust by employing them in his enamelware and ammunitions factories in occupied Poland and the Protectorate of Bohemia and Moravia. He is the subject of the 1982 novel Schindler's Ark and its 1993 film adaptation, Schindler's List, which reflected his life as an opportunist initially motivated by profit, who came to show extraordinary initiative, tenacity, courage, and dedication to save the lives of his Jewish employees.