There are multiple independent categories of evidence that historians use to conclude that the Nazi regime carried out the Holocaust.
The case does not rest on a single document or witness, but on a large body of mutually supporting evidence.
1. Nazi Government Documents
The strongest evidence comes from the Nazis themselves.
The
Wannsee Conference Protocol (January 20, 1942) records senior Nazi officials discussing the coordination of the "Final Solution" of the Jewish question across Europe.
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Orders, memos, reports, transport records, census data, and SS correspondence survive in large numbers. Prosecutors at Nuremberg relied primarily on German-created documents.
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2. Einsatzgruppen Reports
Mobile SS killing units followed the German army into Eastern Europe.
These units filed reports to Berlin documenting mass shootings of Jews and others.
Surviving reports record tens of thousands of executions and were later introduced as evidence in war crimes trials.
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3. Concentration and Extermination Camps
Physical sites still exist.
Auschwitz-Birkenau, Majdanek, Treblinka, Sobibor, Chelmno, and other camps were documented by the Germans and later examined by Allied investigators.
Remains of gas chambers, crematoria, camp infrastructure, prisoner records, and personal belongings have been recovered.
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4. Testimony of Survivors
Thousands of survivors gave accounts.
Their testimonies describe deportations, ghettos, forced labor, selections, mass shootings, gas chambers, starvation, and camp conditions.
Many testimonies were recorded independently in different countries over decades.
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5. Testimony of Nazi Perpetrators
Many Nazi officials admitted their roles.
Adolf Eichmann and numerous SS officers provided statements.
At Nuremberg and subsequent trials, defendants frequently argued they were following orders rather than denying the events occurred.
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6. Allied Investigations and Nuremberg Trials
After the war, Allied powers collected enormous amounts of evidence.
More than 3,000 tons of records were assembled for war crimes investigations.
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The Nuremberg prosecutors intentionally created a historical record based on documents, witnesses, and physical evidence.
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7. Photographs and Film
Visual evidence exists from multiple sources.
German photographs.
Secret photographs taken by prisoners.
Allied footage from liberation of camps.
Aerial reconnaissance images of camp complexes.
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8. Demographic Evidence
Population records show a dramatic loss of European Jewry.
Roughly six million Jews disappeared from the prewar Jewish population of Europe during the period of Nazi rule.
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9. Mass Graves
Thousands of victims have been located in mass burial sites.
Archaeological investigations have confirmed many execution sites associated with Nazi operations in Eastern Europe.
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10. Independent Corroboration
An important point is that these sources come from many different groups:
Nazi officials
German military personnel
Jewish survivors
Non-Jewish witnesses
Allied investigators
Physical remains
Government archives
These sources often originated independently of one another yet point to the same basic conclusion: Nazi Germany implemented a systematic campaign of persecution and mass murder against Jews and other targeted groups during World War II.
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From a historical standpoint, the Holocaust is one of the most extensively documented events of the twentieth century.