The Reichswehr and the Red Army began a secret collaboration in the Soviet Union to evade the Treaty of Versailles occupational agent, the Inter-Allied Commission. In 1926, War games and tests were begun at Kazan and Lipetsk. The centres were used to field test aircraft and armoured vehicles up to the battalion level and housed aerial and armoured warfare schools, through which officers were rotated.[50]
Overy wrote that blitzkrieg as a "coherent military and economic concept has proven a difficult strategy to defend in light of the evidence".[127] Milward's theory was contrary to Hitler's and German planners' intentions. The Germans, aware of the errors of the First World War, rejected the concept of organising its economy to fight only a short war. Therefore, focus was given to the development of armament in depth for a long war, instead of armament in breadth for a short war. Hitler claimed that relying on surprise alone was "criminal" and that "we have to prepare for a long war along with surprise attack". During the winter of 1939–40, Hitler demobilised many troops from the army to return as skilled workers to factories because the war would be decided by production, not a quick "Panzer operation".[128]
Inmates at Birkenau numbered around 100,000 at their peak. They were of many different nationalities, but the vast majority of those that entered the camp were unregistered Jews, many of whom were immediately sent to their deaths in the gas chambers. Women and children stood the least chance of survival, and many died even before arriving at Birkenau due to the appalling conditions of the railway journeys. The unloading platform, where the brisk selection process was conducted, remains. Apart from physically fit men (who often perished later from the rigours of the camp) it was often only an accident of birth that merited a possibility of survival. Large numbers of twins survived until liberation as they were objects of interest to the research of Dr. Josef Mengele - a man disliked even by his Nazi peers.

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.
[t]hroughout the Polish Campaign, the employment of the mechanised 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 armoured 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 as their purpose the physical destruction of the enemy troops. Such was the Vernichtungsgedanke of the Polish campaign.[82]
The Germans isolated all the camps and sub-camps from the outside world and surrounded them with barbed wire fencing. All contact with the outside world was forbidden. However, the area administered by the commandant and patrolled by the SS camp garrison went beyond the grounds enclosed by barbed wire. It included an additional area of approximately 40 square kilometers (the so-called “Interessengebiet” - the interest zone), which lay around the Auschwitz I and Auschwitz II-Birkenau camps.
The film rights to Page’s story were actually first purchased by MGM for $50,000 in the 1960s after Page had similarly ambushed the wife of film producer Marvin Gosch at his leather shop. Mrs. Gosch told the story to her husband, who agreed to produce a film version, even going so far as hiring Casablanca co-screenwriter Howard Koch to write the script. Koch and Gosch began interviewing Schindler Jews in and around the Los Angeles area, and even Schindler himself, before the project stalled, leaving the story unknown to the public at large.
The concepts associated with the term blitzkrieg—deep penetrations by armour, large encirclements, and combined arms attacks—were largely dependent upon terrain and weather conditions. Where the ability for rapid movement across "tank country" was not possible, armoured penetrations often were avoided or resulted in failure. Terrain would ideally be flat, firm, unobstructed by natural barriers or fortifications, and interspersed with roads and railways. If it were instead hilly, wooded, marshy, or urban, armour would be vulnerable to infantry in close-quarters combat and unable to break out at full speed.[citation needed] Additionally, units could be halted by mud (thawing along the Eastern Front regularly slowed both sides) or extreme snow. Operation Barbarossa helped confirm that armour effectiveness and the requisite aerial support were dependent on weather and terrain.[68] It should however be noted that the disadvantages of terrain could be nullified if surprise was achieved over the enemy by an attack through areas considered natural obstacles, as occurred during the Battle of France when the German blitzkrieg-style attack went through the Ardennes.[69] Since the French thought the Ardennes unsuitable for massive troop movement, particularly for tanks, they were left with only light defences which were quickly overrun by the Wehrmacht. The Germans quickly advanced through the forest, knocking down the trees the French thought would impede this tactic.[70]
All of the musicians were required to perform forced labour in addition to their daily concerts.  They were also subject to regular selections.  As was the case in other camps, the musicians were required to play marches at the main gate when the work commandos left the camp in the morning and returned in the evening.  Due to the forced labour, frequent selections, suicides and generally poor health of the musicians, by the end of the year the orchestra was shrinking rather than growing.  Simultaneously, the sub-camp commander Johann Schwarzhuber, who provided the men with instruments and sheet music, increased his demands, seriously challenging Kopka's abilities.  The latter became increasingly dependent on the arranging and conducting skills of Laks, who grew skilled at composing music with interchangeable parts in case of the sudden disappearance of a musician.  Eventually Laks became the de facto conductor, a position made official when Kopka was sent to the front with the German army.

Similarly, in Ordinary Men (1992), Christopher Browning examined the deeds of German Reserve Police Battalion 101 of the Ordnungspolizei ("order police"), used to commit massacres and round-ups of Jews, as well as mass deportations to the death camps. The members of the battalion were middle-aged men of working-class background from Hamburg, who were too old for regular military duty. They were given no special training. During the murder of 1,500 Jews from Józefów in Poland, their commander allowed them to opt out of direct participation. Fewer than 12 men out of a battalion of 500 did so. Influenced by the Milgram experiment on obedience, Browning argued that the men killed out of peer pressure, not bloodlust.[471]
The wounds of the Holocaust–known in Hebrew as Shoah, or catastrophe–were slow to heal. Survivors of the camps found it nearly impossible to return home, as in many cases they had lost their families and been denounced by their non-Jewish neighbors. As a result, the late 1940s saw an unprecedented number of refugees, POWs and other displaced populations moving across Europe.

Dunin-Wasowicz, Krzysztof (1980). "Forced Labor and Sabotage in the Nazi Concentration Camps". In Gutman, Yisrael; Saf, Avital. The Nazi concentration Camps: Structure and Aims, the Image of the Prisoner, the Jews in the Camps: Proceedings of the Fourth Yad Vashem International Historical Conference, Jerusalem, January 1980. Jerusalem: Yad Vashem. pp. 133–142.
To achieve a breakout, armored forces themselves would attack the enemy's defensive line directly, supported by their own infantry (Panzergrenadiers), artillery fire and aerial bombardment in order to create a breach in the enemy's line. Through this breach the tanks could break through without the traditional encumbrance of the slow logistics of a pure infantry regiment. The breaching force never lost time by 'stabilising its flanks' or by regrouping; rather it continued the assault in a towards the interior of the enemies lines, sometimes diagonally across them. This point of breakout has been labeled a "hinge", but only because a change in direction of the defender's lines is naturally weak and therefore a natural target for blitzkrieg assault.

This is not a pleasant site, not one that will distract from the pressures of everyday existence. But Birkenau, the largest and most lethal of the Auschwitz camps, is as much a part of the world as any aspiration for freedom and peace. In this sense, the authors and publishers of this exhibition feel we need to constantly explore this place and the ideas that created it, in the hope that eventually we will understand why people do such terrible things to other human beings, and why some were able, despite the tremendous role luck played, to find the strength to survive it. The search for this kind of meaning has, as paradoxical as it may sound, enriched our lives.

On 1 August 1940, Governor-General Hans Frank issued a decree requiring all Kraków Jews to leave the city within two weeks. Only those who had jobs directly related to the German war effort would be allowed to stay. Of the 60,000 to 80,000 Jews then living in the city, only 15,000 remained by March 1941. These Jews were then forced to leave their traditional neighbourhood of Kazimierz and relocate to the walled Kraków Ghetto, established in the industrial Podgórze district.[41][42] Schindler's workers travelled on foot to and from the ghetto each day to their jobs at the factory.[43] Enlargements to the facility in the four years Schindler was in charge included the addition of an outpatient clinic, co-op, kitchen, and dining room for the workers, in addition to expansion of the factory and its related office space.[44]