In the first phase of World War II in Europe, Germany sought to avoid a long war. Germany's strategy was to defeat its opponents in a series of short campaigns. Germany quickly overran much of Europe and was victorious for more than two years by relying on a new military tactic called the "Blitzkrieg" (lightning war). Blitzkrieg tactics required the concentration of offensive weapons (such as tanks, planes, and artillery) along a narrow front. These forces would drive a breach in enemy defenses, permitting armored tank divisions to penetrate rapidly and roam freely behind enemy lines, causing shock and disorganization among the enemy defenses. German air power prevented the enemy from adequately resupplying or redeploying forces and thereby from sending reinforcements to seal breaches in the front. German forces could in turn encircle opposing troops and force surrender.
The Holocaust was the systematic annihilation of six million Jews by the Nazis during World War 2. In 1933 nine million Jews lived in the 21 countries of Europe that would be military occupied by Germany during the war. By 1945 two out of every three European Jews had been killed. 1.5 million children were murdered. This figure includes more than 1.2 million Jewish children, tens of thousands of Gypsy children and thousands of handicapped children.
In June 1945 the Soviet authorities took over Auschwitz I and converted it into a POW camp for German prisoners. The hospital had to move beyond the camp perimeter into former administrative buildings, where it functioned until October 1945.[253] Many of the barracks at Birkenau were taken apart by civilians, who used the materials to rebuild their own homes, which had been levelled out in the construction of Auschwitz II. The poorest residents sifted the crematoria ashes in search of nuggets from melted gold, before warning shots were fired.[254] The POW camp for German prisoners of war was used until 1947 by the Soviet NKVD (People's Commissariat for Internal Affairs).[255] The NKVD and its Polish counterpart, the MBP, used the Auschwitz Neu-Dachs sub-camp at Jaworzno to the north of Oświęcim as a concentration camp from 1945 to 1956.[256] The Soviets dismantled and exported the IG Farben factories to the USSR.[257] Meanwhile, Soviet and Polish investigators worked to document the war crimes of the SS.[258] After the site became a museum in 1947, exhumation work lasted for more than a decade.[184]

A second roll call took place at seven in the evening after the long day's work.[118] Prisoners might be hanged or flogged in the course of it. If a prisoner was missing, the others had to remain standing until he or she was found or the reason for the absence discovered, even if it took hours. On 6 July 1940, roll call lasted 19 or 20 hours because of the escape of a Polish prisoner, Tadeusz Wiejowski; following another escape in 1941, a group of prisoners was sent to block 11 to be starved to death.[119] After roll call, prisoners were allowed to retire to their blocks for the night and receive their bread rations and water. Curfew was at nine o'clock. Inmates slept in long rows of brick or wooden bunks, lying in and on their clothes and shoes to prevent them from being stolen.[120] The wooden bunks had blankets and paper mattresses filled with wood shavings; in the brick barracks, inmates lay on straw.[121] According to Nyiszli:
SS-Obergruppenführer Reinhard Heydrich, head of the Reich Main Security Office (Reichssicherheitshauptamt or RSHA), convened what became known as the Wannsee Conference on 20 January 1942 at Am Großen Wannsee 56–58, a villa in Berlin's Wannsee suburb.[256][257] The meeting had been scheduled for 9 December 1941, and invitations had been sent on 29 November, but it had been postponed.[258]
Nazi racial policy aimed at forcing Jews to emigrate.[109] Fifty thousand German Jews had left Germany by the end of 1934,[110] and by the end of 1938, approximately half the German Jewish population had left the country.[109] Among the prominent Jews who left was the conductor Bruno Walter, who fled after being told that the hall of the Berlin Philharmonic would be burned down if he conducted a concert there.[111] Albert Einstein, who was in the United States when Hitler came to power, never returned to Germany; he was expelled from the Kaiser Wilhelm Society and the Prussian Academy of Sciences and his citizenship was revoked.[112] Other Jewish scientists, including Gustav Hertz, lost their teaching positions and left the country.[113] On 12 March 1938, Germany annexed Austria. Austrian Nazis broke into Jewish shops, stole from Jewish homes and businesses, and forced Jews to perform humiliating acts such as scrubbing the streets or cleaning toilets.[114] Jewish businesses were "Aryanized", and all the legal restrictions on Jews in Germany were imposed.[115] In August that year, Adolf Eichmann was put in charge of the Central Agency for Jewish Emigration in Vienna (Zentralstelle für jüdische Auswanderung in Wien). About 100,000 Austrian Jews had left the country by May 1939, including Sigmund Freud and his family, who moved to London.[116] The Évian Conference was held in July 1938 by 32 countries as an attempt to help the increased refugees from Germany, but aside from establishing the largely ineffectual Intergovernmental Committee on Refugees, little was accomplished and most countries participating did not increase the number of refugees they would accept.[117]
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.

In his 1965 essay "Command and Compliance", which originated in his work as an expert witness for the prosecution at the Frankfurt Auschwitz Trials, the German historian Hans Buchheim wrote there was no coercion to murder Jews and others, and all who committed such actions did so out of free will. Buchheim wrote that chances to avoid executing criminal orders "were both more numerous and more real than those concerned are generally prepared to admit",[468] and that he found no evidence that SS men who refused to carry out criminal orders were sent to concentration camps or executed.[469] Moreover, SS rules prohibited acts of gratuitous sadism, as Himmler wished for his men to remain "decent"; acts of sadism were carried out on the initiative of those who were either especially cruel or wished to prove themselves ardent National Socialists.[468] Finally, he argued that those of a non-criminal bent who committed crimes did so because they wished to conform to the values of the group they had joined and were afraid of being branded "weak" by their colleagues if they refused.[470]

The victories of Operation Barbarossa in the summer and fall of 1941 against Hitler's new enemy, the Soviet Union, led to dramatic changes in Nazi anti-Jewish ideology and the profile of prisoners brought to Auschwitz.[37] Construction on Auschwitz II-Birkenau began in October 1941 to ease congestion at the main camp. Reichsführer-SS Heinrich Himmler, head of the Schutzstaffel (SS), intended the camp to house 50,000 prisoners of war, who would be interned as forced laborers. Plans called for the expansion of the camp first to house 150,000 and eventually as many as 200,000 inmates.[38] An initial contingent of 10,000 Soviet prisoners of war arrived at Auschwitz I in October 1941, but by March 1942 only 945 were still alive, and these were transferred to Birkenau, where most of them died from disease or starvation by May.[39] By this time the Nazis had decided to annihilate the Jewish people,[40] so Birkenau became a labor and extermination camp.[39][41]
The Nazis then combined their racial theories with the evolutionary theories of Charles Darwin to justify their treatment of the Jews. The Germans, as the strongest and fittest, were destined to rule, while the weak and racially adulterated Jews were doomed to extinction. Hitler began to restrict the Jews with legislation and terror, which entailed burning books written by Jews, removing Jews from their professions and public schools, confiscating their businesses and property and excluding them from public events. The most infamous of the anti-Jewish legislation were the Nuremberg Laws, enacted on September 15, 1935. They formed the legal basis for the Jews' exclusion from German society and the progressively restrictive Jewish policies of the Germans.
The gas chambers in the Auschwitz complex constituted the largest and most efficient extermination method employed by the Nazis. Four chambers were in use at Birkenau, each with the potential to kill 6,000 people daily. They were built to look like shower rooms in order to confuse the victims. New arrivals at Birkenau were told that they were being sent to work, but first needed to shower and be disinfected. They would be led into the shower-like chambers, where they were quickly gassed to death with the highly poisonous Zyklon B gas.
But the personalities and characteristics of human beings cannot be spliced. Sometimes character flaws, such as hubris, also lead to great achievements through a willingness to attempt something most people never would. Oskar’s espionage activities on behalf of Germany, while regrettable to enemies of Germany, later put him in a position to save many lives.
Responding to domestic pressures to act on behalf of Jewish refugees, U.S. Pres. Franklin D. Roosevelt convened, but did not attend, the Évian Conference on resettlement, in Évian-les-Bains, France, in July 1938. In his invitation to government leaders, Roosevelt specified that they would not have to change laws or spend government funds; only philanthropic funds would be used for resettlement. Britain was assured that Palestine would not be on the agenda. The result was that little was attempted and less accomplished.
In most ghettos, Nazis ordered the Jews to establish a Judenrat (Jewish council) to administer Nazi demands and to regulate the internal life of the ghetto. The Nazis routinely ordered deportations from the ghettos. In some of the large ghettos, 1,000 people per day were sent by rail to concentration and extermination camps. To get them to cooperate, the Nazis told the Jews they were being transported elsewhere for labor.
Reading the comments below, it is interesting to see how little people know about history and what actually happened during WW2. Is the education system so bad in America that one person doesn't know that Poland was invaded in 1939 by the Nazi - pick up a book! The lesson of Auschwitz should be learnt, but once should also realise that it wasn't just the Jews who were murdered. There were gypsies, native poles, political opponents, homosexuals to name but a few who were exterminated in the gas chambers or worked to death. By studying and learning from the past can we help avoid these situations again. However in this climate I sometimes wonder if anything has been learnt.
A parallel system operated later at Birkenau in 1942-43, except that for the majority the 'showers' proved to be gas chambers. Only about 10 percent of Jewish transports were registered, disinfected, shaven and showered in the 'central sauna' before being assigned barracks. In May 1944, a spur line was built right into the camp to accelerate and simplify the handling of the tens of thousands of Hungarian and other Jews deported in the spring and summer of 1944.

After WWII had ended, photographs of the Holocaust stunned the public. Newspapers in the United States had reported on the oppression of the Jews in Germany during the war. In 1942, many newspapers were writing details of the Holocaust, but these stories were short and were not widely read. In 1943, after sources had confirmed the killings of at least two million Jews in concentration camps across Europe a Gallup poll found that less than half of Americans believed these reports to be true; 28% thought they were “just a rumor”. The reports were unconfirmed and sometimes denied by the United States government.

Although many people responded with obstructionism and doubt,  several rescue operations were run throughout Axis-controlled Europe. Some were the work of prominent individuals like Raoul Wallenberg and Carl Lutz who worked largely alone while other operations were far more complex. A network of Catholic bishops and clergymen organized local protests and shelter campaigns throughout much of Europe that are today estimated to have saved 860,000 lives. Danish fishermen clandestinely ferried more than 7,000 Jews into neutral Sweden while the French town of Chambon-sur-Lignon sheltered between 3,000 and 5,000 refugees.
Fewer than 200 Jews escaped from the camps. Herman Shine, one of the last survivors to have escaped Auschwitz, died in July 2018. He was born in Berlin to a Polish father and they were arrested in that city in 1939. Along with 1,700 other Polish Jews, they were deported to Sachsenhausen. To survive, Shine claimed to be a roofer and learned how to build roofs before being transferred to Auschwitz in 1942.
Los recintos, las alambradas, las torretas de vigilancia, las casamatas, las horcas, las cámaras de gas y los hornos crematorios de este campo de concentración y exterminio, que fue el más vasto de los creados por el Tercer Reich, dan fe de las condiciones en que se perpetró el genocidio nazi. Según los trabajos de investigación histórica, entre 1.100.000 y 1.500.000 prisioneros –en gran parte judíos– fueron sistemáticamente privados de alimentación, torturados y asesinados en este campo, símbolo de la crueldad ejercida por el hombre contra sus semejantes en el siglo XX.
Although the Germans destroyed parts of the camps before abandoning them in 1945, much of Auschwitz I and Auschwitz II (Birkenau) remained intact and were later converted into a museum and memorial. The site has been threatened by increased industrial activity in Oświęcim. In 1996, however, the Polish government joined with other organizations in a large-scale effort to ensure its preservation. Originally named Auschwitz Concentration Camp, the memorial was designated a UNESCO World Heritage site in 1979. It was renamed “Auschwitz-Birkenau. The Nazi German Concentration and Extermination Camp (1940–1945)” in 2007.
On 15 October 1944 a train carrying 700 men on Schindler's list was initially sent to the concentration camp at Gross-Rosen, where the men spent about a week before being re-routed to the factory in Brünnlitz.[66] Three hundred female Schindlerjuden were similarly sent to Auschwitz, where they were in imminent danger of being sent to the gas chambers. Schindler's usual connections and bribes failed to obtain their release. Finally after he sent his secretary, Hilde Albrecht, with bribes of black market goods, food and diamonds, the women were sent to Brünnlitz after several harrowing weeks in Auschwitz.[67]