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![Poles walk among the ruins of besieged Warsaw. [LCID: 47270]](https://encyclopedia.ushmm.org/images/thumb/2adc847c-f75f-4897-ad13-554b935e0949.jpg)
Featured Article
Invasion of Poland, Fall 1939
German troops invaded Poland on September 1, 1939, triggering World War II. In response to German aggression, Great Britain and France declared war on Nazi Germany.
Must Reads
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![Jews from Subcarpathian Rus get off the deportation train and assemble on the ramp at Auschwitz-Birkenau. May 1944.]()
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Introduction to the Holocaust -
![German troops parade through Warsaw after the invasion of Poland. [LCID: 80487]]()
Article
Invasion of Poland, Fall 1939 -
![An aerial photograph of Babi Yar taken by the German air force. [LCID: 23809]]()
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Mass Shootings at Babyn Yar (Babi Yar) -
![German troops on the move during an anti-partisan operation.]()
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World War II: In Depth -
![SS troops lead a group of Poles into the forest near Witaniow for execution]()
Discussion Question
What does war make possible? -
![Heinrich Himmler (seated, center), chief of the SS, with Reinhard Heydrich (standing, left), chief of the Reich Main Security Office ... [LCID: 79625]]()
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Reich Security Main Office (RSHA) -
![First grade pupils, both Jewish and non-Jewish, study in a classroom in a public school in Hamburg. [LCID: 38317]]()
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The Role of Academics and Teachers -
![Poster: "Students/Be the Führer's propagandists." [LCID: p246h]]()
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University Student Groups in Nazi Germany
![German troops parade through Warsaw after the invasion of Poland. [LCID: 80487]](https://encyclopedia.ushmm.org/images/thumb/6b473ced-71b7-474b-9519-969ed787dda8.jpg)
![An aerial photograph of Babi Yar taken by the German air force. [LCID: 23809]](https://encyclopedia.ushmm.org/images/thumb/14949661-c40c-4d3a-ba27-0131060d3c6d.jpg)
![Heinrich Himmler (seated, center), chief of the SS, with Reinhard Heydrich (standing, left), chief of the Reich Main Security Office ... [LCID: 79625]](https://encyclopedia.ushmm.org/images/thumb/dd9ee10c-c235-4265-9d37-d525a28ff28b.jpg)
![First grade pupils, both Jewish and non-Jewish, study in a classroom in a public school in Hamburg. [LCID: 38317]](https://encyclopedia.ushmm.org/images/thumb/5c38a82d-4d47-47ec-b4cf-0fa6e80f807d.jpg)
![Poster: "Students/Be the Führer's propagandists." [LCID: p246h]](https://encyclopedia.ushmm.org/images/thumb/b8ca057f-64ef-4bb5-8c55-74612681ab12.jpg)
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ID Cards
Learn more about personal experiences during the Holocaust
Timeline of Events
Explore a timeline of events that occurred before, during, and after the Holocaust.
Discussion Questions
How and why was the Holocaust possible?