TIL that around 6 million Polish citizens —nearly 21.4% of Poland's population at the time — died between 1939 and 1945 as a result of the German occupation of the country. It is estimated 90% of those deaths were non-military losses, i.e. murder.

Here are some historical sources and secondary accounts that support the idea that Nazis transported the dead on trains during World War II:

Eyewitness Testimonies: Numerous survivors of the Holocaust and other victims of Nazi atrocities have given testimony about the use of trains to transport the dead. These testimonies can be found in various historical archives and libraries, such as the United States Holocaust Memorial Museum and the International Tracing Service.

Historical Documents: Official German records, as well as captured German military and police documents, provide evidence of the use of trains to transport the dead during the Holocaust. These documents can be found in various archives and libraries, such as the US National Archives and the archives of the International Criminal Tribunal for the former Yugoslavia.

Historical Studies and Research: Numerous historical studies and research have been conducted on the Holocaust and the use of trains in the transport of the dead. Some of these studies have been published in academic journals, books, and other scholarly works.

Note that this information is widely available in public historical records and can also be easily found with a quick online search using keywords like "Holocaust" and "transport of the dead in trains".

Photos and Images: There are also photos and images of the trains used to transport the dead that have been preserved and are available in various archives and libraries.

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