In 1914, German strategic thinking derived from the writings of Carl von Clausewitz (June 1, 1780 – November 16, 1831), Helmuth von Moltke the Elder (26 October 1800 – 24 April 1891) and Alfred von Schlieffen (28 February 1833 – 4 January 1913), who advocated manoeuvre, mass and envelopment to create the conditions for a decisive battle (Vernichtungsschlacht). During the war, officers such as Willy Rohr developed tactics to restore manoeuvre on the battlefield. Specialist light infantry (Sturmtruppen, "storm troops") were to exploit weak spots to make gaps for larger infantry units to advance with heavier weapons and exploit the success, leaving isolated strong points to troops following up. Infiltration tactics were combined with short hurricane artillery bombardments using massed artillery, devised by Colonel Georg Bruchmüller. Attacks relied on speed and surprise rather than on weight of numbers. These tactics met with great success in Operation Michael, the spring offensive of 1918 and restored temporarily the war of movement, once the Allied trench system had been overrun. The German armies pushed on towards Amiens and then Paris, coming within 120 kilometres (75 mi) before supply deficiencies and Allied reinforcements halted the advance.[27] Historian James Corum criticised the German leadership for failing to understand the technical advances of the First World War, having given tank production the lowest priority and having conducted no studies of the machine gun prior to that war.[28]

Oskar Schindler was born into a German Catholic family on April 28, 1908. After attending trade schools, he worked for his father’s farm machinery company. He worked for German intelligence and later joined the Nazi Party. An opportunist businessman with a taste for the finer things in life, he seemed an unlikely candidate to become a wartime hero. During the war, however, he operated a factory that employed more than 1,000 Polish Jews, saving them from concentration camps and extermination. In 1993 his story was made into the Steven Spielberg feature film Schindler's List.
The mass killings of Jews in the occupied Soviet territories were assigned to four SS formations called Einsatzgruppen ("task groups"), which were under Heydrich's overall command. Similar formations had been used to a limited extent in Poland in 1939, but the ones operating in the Soviet territories were much larger.[242] The Einsatzgruppen's commanders were ordinary citizens: the great majority were professionals and most were intellectuals.[243] By the winter of 1941–1942, the four Einsatzgruppen and their helpers had killed almost 500,000 people.[244] The largest massacre of Jews by the mobile killing squads in the Soviet Union was at a ravine called Babi Yar outside Kiev,[245] where 33,771 Jews were killed in a single operation on 29–30 September 1941.[246][n] A mixture of SS and Security Police, assisted by Ukrainian police, carried out the killings.[248] Although they did not actively participate in the killings, men of the German 6th Army helped round up the Jews of Kiev and transport them to be shot.[249] By the end of the war, around two million are thought to have been victims of the Einsatzgruppen and their helpers in the local population and the German Army. Of those, about 1.3 million were Jews and up to a quarter of a million Roma.[250]
On 27 January 1945, the 60th Army of the First Ukrainian Front, a unit of the Soviet Army, opened the gates and entered the Auschwitz camp complex. The liberators discovered around 7,000 surviving prisoners across the three main camps of Auschwitz I, Auschwitz-Birkenau and Buna Monowitz. Amongst the survivors were 180 children; 52 of them under the age of eight.

In the Sinai and Palestine Campaign, operations involved some aspects of what would later be called blitzkrieg.[38] Key elements in the "blitzkrieg warfare" at the decisive Battle of Megiddo included concentration, surprise and speed; success depended on attacking only in terrain favoring the movement of large formations around the battlefield and tactical improvements in the British artillery and infantry attack.[39][40] General Edmund Allenby used infantry to attack the strong Ottoman front line in co-operation with supporting artillery, augmented by the guns of two destroyers.[41][42] Through constant pressure by infantry and cavalry, two Ottoman armies in the Judean Hills were kept off-balance and virtually encircled during the Battles of Sharon and Nablus (Battle of Megiddo).[43]
Once the strategic Schwerpunkt had been identified, the attack could commence, using the concept of Kesselschlacht (“cauldron battle”). A frontal attack would immobilize the enemy while forces on the flanks would execute a double envelopment, forming a pocket called a Kessel (“cauldron”) around the enemy. Once surrounded, the opposing army, demoralized and with no chance of escape, would face the choice of annihilation or surrender.
The commander of Auschwitz-Birkenau, Rudolf Höss, stated in his autobiography that in 1941 (no exact date is given) he was summoned to Berlin, where Himmler informed him that Hitler had issued an order to solve the “Jewish Question” for good, and that the order was to be implemented by the SS. “The existing extermination places in the east are unsuited to a large scale, long-term action. I have designated Auschwitz for this purpose,” Himmler said.

Political dissidents, trade unionists, and Social Democrats were among the first to be arrested and incarcerated in concentration camps. Under the Weimar government, centuries-old prohibitions against homosexuality had been overlooked, but this tolerance ended violently when the SA (Storm Troopers) began raiding gay bars in 1933. Homosexual intent became just cause for prosecution. The Nazis arrested German and Austrian male homosexuals—there was no systematic persecution of lesbians—and interned them in concentration camps, where they were forced to wear special yellow armbands and later pink triangles. The goal of persecuting male homosexuals was either for reeducation—what might now be called conversion therapy—or punishment. Jehovah’s Witnesses were a problem for the Nazis because they refused to swear allegiance to the state, register for the draft, or utter the words “Heil Hitler.” As a result, the Nazis imprisoned many of the roughly 20,000 Jehovah’s Witnesses in Germany. They could be released from concentration camps if they signed a document renouncing their faith and promising not to proselytize. Few availed themselves of that option, preferring martyrdom to apostasy. Germans of African descent—many of whom, called “Rhineland bastards” by the Nazis, were the offspring of German mothers and French colonial African troops who had occupied the Rhineland after World War I—were also persecuted by the Nazis. Although their victimization was less systematic, it included forced sterilization and, often, internment in concentration camps. The fear was that they would “further pollute” and thereby diminish the race. The Nazis also singled out the Roma and Sinti, pejoratively known as Gypsies. They were the only other group that the Nazis systematically killed in gas chambers alongside the Jews. For the Roma and Sinti, too, racial pollution and their depiction as asocials was the justification for their persecution and murder.
The number of Afro-Germans in Germany when the Nazis came to power is variously estimated at 5,000–25,000.[454] It is not clear whether these figures included Asians. Although blacks, including prisoners of war, in Germany and German-occupied Europe were subjected to incarceration, sterilization, murder, and other abuse, there was no programme to kill them all as there was for the Jews.[455]
SS officers, including the infamous Dr. Josef Mengele, would conduct selections among these lines, sending most victims to one side and thus condemning them to death in the gas chambers. A minority was sent to the other side, destined for forced labor. Those who were sent to their deaths were killed that same day and their corpses were burnt in the crematoria. Those not sent to the gas chambers were taken to “quarantine,” where their hair was shaved, striped prison uniforms distributed, and registration took place. Prisoners’ individual registration numbers were tattooed onto their left arm.
Between 1942 and 1944, the SS authorities at Auschwitz established 44 subcamps. Some of them were established within the officially designated “development” zone, including Budy, Rajsko, Tschechowitz, Harmense, and Babitz. Others, such as Blechhammer, Gleiwitz, Althammer, Fürstengrube, Laurahuette, and Eintrachthuette were located in Upper Silesia north and west of the Vistula River. Some subcamps, such as Freudenthal and Bruenn (Brno), were located in Moravia.
Finland was pressured in 1942 to hand over its 150–200 non-Finnish Jews to Germany. After opposition from the government and public, eight non-Finnish Jews were deported in late 1942; only one survived the war.[173] Japan had little antisemitism in its society and did not persecute Jews in most of the territories it controlled. Jews in Shanghai were confined, but despite German pressure they were not killed.[174]
Defined by the religion of their grandparents rather than by their own beliefs, Jews were viewed as having impure blood lines. The new laws were taught in schools, cementing anti-Semitism in German culture. Most Germans kept quiet, often benefiting when Jews lost jobs and businesses. Persecution of other minorities also escalated: the police were given new powers to arrest homosexuals and compulsory abortions were administered to women considered to be ‘hereditarily ill’.

The Polish government-in-exile in London learned about the extermination camps from the Polish leadership in Warsaw, who from 1940 "received a continual flow of information about Auschwitz", according to historian Michael Fleming.[333] This was in large measure thanks to Captain Witold Pilecki of the Polish Home Army, who allowed himself to be arrested in Warsaw and spent 945 days in Auschwitz from September 1940 until April 1943, organizing the resistance movement inside the camp.[334]
In late January 1945, SS and police officials forced 4,000 prisoners to evacuate Blechhammer on foot. Blechhammer was a subcamp of Auschwitz-Monowitz. The SS murdered about 800 prisoners during the march to the Gross-Rosen concentration camp. SS officials also killed as many as 200 prisoners left behind in Blechhammer as a result of illness or unsuccessful attempts to hide. After a brief delay, the SS transported around 3,000 Blechhammer prisoners from Gross-Rosen to the Buchenwald concentration camp in Germany.
In fall 1941, the Nazis began transporting Jews out of the ghetto. Most of them were sent to the Bełżec extermination camp and killed.[45] On 13 March 1943, the ghetto was liquidated and those still fit for work were sent to the new concentration camp at Płaszów.[46] Several thousand not deemed fit for work were sent to extermination camps and killed. Hundreds more were killed on the streets by the Nazis as they cleared out the ghetto. Schindler, aware of the plans because of his Wehrmacht contacts, had his workers stay at the factory overnight to prevent them coming to harm.[47] Schindler witnessed the liquidation of the ghetto and was appalled. From that point forward, says Schindlerjude Sol Urbach, Schindler "changed his mind about the Nazis. He decided to get out and to save as many Jews as he could."[48]