The Holocaust was the systematic, state-organised murder of six million Jews by the Nazi regime and its collaborators between 1941 and 1945. It was also the murder of millions of others — Soviet civilians and prisoners of war, Roma, disabled people, political opponents, gay men — in a programme of ideologically driven mass killing that had no precedent in modern history. Understanding the Holocaust means understanding both the specific ideological obsessions of Nazism and the more troubling question of how ordinary people, in a modern European state, became perpetrators of genocide.
Persecution and Exclusion (1933–39)
The Holocaust did not begin with death camps. It began with laws. Within months of Hitler’s appointment as Chancellor in January 1933, Jews were being excluded from the civil service, the professions, and public life. The Nuremberg Laws of 1935 stripped Jews of German citizenship and prohibited marriage between Jews and non-Jews. Jewish businesses were subject to boycotts, then ‘Aryanisation’ — forced transfer to non-Jewish ownership at a fraction of their value. By 1938, Jews had been comprehensively excluded from German economic and social life.
The violence of Kristallnacht in November 1938 — when Nazi stormtroopers and ordinary Germans destroyed thousands of Jewish-owned businesses and synagogues, killed dozens, and sent thirty thousand to concentration camps — made clear that persecution would not stop at legal discrimination. For those who could afford to leave Germany, emigration was the only option. Many could not. And when Germany went to war in 1939 and rapidly conquered Poland — home to the largest Jewish population in Europe — emigration ceased to be possible. The Nazi regime now controlled millions of Jews with nowhere to go.
The Road to Genocide (1939–42)
The decision to murder all of Europe’s Jews was not made at a single moment. It emerged from the interaction of ideology, war, and bureaucratic improvisation. In occupied Poland from 1939, Jews were concentrated in overcrowded ghettos where disease and starvation killed tens of thousands. When Germany invaded the Soviet Union in June 1941, mobile killing units — the Einsatzgruppen — followed the advancing armies, shooting Jews, Soviet commissars, and others in mass executions. By the end of 1941, the Einsatzgruppen had killed over half a million people.
The Wannsee Conference of January 1942 did not decide on genocide — that decision had effectively already been made — but it coordinated the bureaucratic machinery for implementing it across Nazi-controlled Europe. The ‘Final Solution’ moved from shooting to gassing: more efficient, less psychologically damaging to the perpetrators. Six death camps were established in occupied Poland — Auschwitz-Birkenau, Treblinka, Sobibór, Bełżec, Chełmno, and Majdanek — to which Jews from across Europe would be transported and murdered on an industrial scale.
Auschwitz and the Death Camps (1942–45)
Auschwitz-Birkenau was the largest of the Nazi killing centres, combining a concentration camp, a forced labour camp, and extermination facilities in a single complex in occupied Poland. Between 1942 and 1944, trains arrived continuously from across Nazi-occupied Europe — from France, the Netherlands, Belgium, Greece, Hungary, and elsewhere — carrying Jewish families who had been told they were being ‘resettled’. On arrival, SS doctors conducted ‘selections’: those deemed fit for labour were sent to the camp; those deemed unfit — the elderly, the young, the sick — were gassed immediately. An estimated 1.1 million people were murdered at Auschwitz alone.
The Holocaust was not carried out only by a fanatical SS elite. Historians have documented the participation of ordinary German police battalions, local collaborators across Europe, railway workers, civil servants, and bystanders who looked away. Christopher Browning’s study of Reserve Police Battalion 101, whose members were ordinary middle-aged German men, demonstrated that most chose to participate in mass shootings when given the option to refuse. The question of perpetrator motivation — ideology, conformity, careerism, peer pressure — has driven historical debate for decades and carries implications that extend far beyond the Nazi case.
Memory, Denial, and the Long Shadow (1945–present)
When Allied forces liberated the concentration camps in spring 1945, the evidence confronting them — and the world — was overwhelming. The Nuremberg trials of 1945–46 established the principle that crimes against humanity could be prosecuted under international law and that following orders was not a sufficient defence. The state of Israel, founded in 1948, was shaped in fundamental ways by the Holocaust and the failure of the world’s states to offer sanctuary to Jewish refugees before and during the war. The Holocaust has since become a central reference point in international human rights discourse — the crime that the phrase ‘Never Again’ was coined to prevent.
Yet the Holocaust’s memory has been contested from the start. Holocaust denial — the deliberate falsification of historical evidence to deny or minimise the genocide — emerged almost immediately after the war and has persisted as a form of antisemitism. The question of how different European nations remember or suppress their complicity in the Holocaust remains politically charged. Poland, France, Hungary, and others have all struggled with the gap between official commemorative culture and historical evidence of local collaboration. Memory is not simply the preservation of the past; it is a political act, shaped by what communities find bearable to acknowledge.
Key Dates
| Year | Event |
|---|---|
| 1933 | Hitler appointed Chancellor; first concentration camps opened; boycott of Jewish businesses |
| 1935 | Nuremberg Laws strip Jews of citizenship; racial classification enforced |
| 1938 Nov | Kristallnacht — pogrom across Germany and Austria; 30,000 Jews arrested |
| 1939 | Germany invades Poland; 3.3 million Polish Jews under Nazi control; ghettos established |
| 1941 Jun | Operation Barbarossa; Einsatzgruppen begin mass shootings in Soviet territories |
| 1941 Dec | Chełmno death camp opens — first use of gas vans for mass killing |
| 1942 Jan | Wannsee Conference coordinates the ‘Final Solution’ across occupied Europe |
| 1942 | Operation Reinhard death camps operational: Treblinka, Sobibór, Bełżec |
| 1942–44 | Auschwitz-Birkenau at peak operation; Jews deported from across occupied Europe |
| 1943 Apr | Warsaw Ghetto Uprising — Jewish resistance fighters hold off SS for nearly a month |
| 1944 Jun | D-Day; Hungarian Jews (437,000) deported to Auschwitz in eight weeks |
| 1945 Jan | Auschwitz liberated by Soviet forces; death marches westward |
| 1945–46 | Nuremberg trials; senior Nazis prosecuted for crimes against humanity |
| 1948 | State of Israel founded; UN Genocide Convention adopted |
Download this guide as a PDF
A free, print-ready PDF of this guide is available to download and share.
Go Deeper
For a full collection of podcast episodes on the Holocaust — persecution, the camps, perpetrators, memory, and denial — visit the Holocaust episode collection.
For regular analysis connecting past and present, join the free Explaining History Substack.
