The second half of Claude Lanzmann's Shoah (1985) focuses on explicit details of how the Nazi's machinery of mass murder worked, on the industrialization and logistics of the business end of it. Lanzmann also focuses on just how incomprehensible the scale of violence was, how no one who had not seen it with their own eyes could believe that humans were capable of such inhumanity, how even victims mere moments from their death could scarcely believe it. And we end with stories of resistance and revolt.

Shoah doesn't deal with the "why" of the Holocaust, but the "how", and Lanzmann presses his interviewees - victims, witnesses, and perpetrators - on that "how" to explicit and horrifying detail. But this detail must be seen, must be known, must be believed, to truly never let it happen again, to be able to stand against genocide no matter where it takes place now, from the US's deportation machines to the murder of thousands of children in Gaza.