December 12, 1941 — Hitler announces the destruction of the Jews

Of all things, it was the entry of the United States into the war that prompted Hitler to move the Holocaust into high gear. Now that the Americans were in it, the usefulness of the remaining Jews as hostages was at an end, and Hitler saw no reason to delay the complete destruction of the Jewish race – all the ones he could get his hands on, at least – a moment longer.

This announcement was made to a group of fifty or so of the highest ranking Nazis, chiefly the politicians and bureaucrats who formed the Third Reich’s top echelon, whom Hitler had summoned to a meeting in the Reich Chancellory. Himmler, Goebbels and Bormann are all known to have attended the meeting. Moreover, documents related to this meeting – including Goebbels’ diaries – make it clear that the plan to exterminate the Jews was not carried out without Hitler’s knowledge or responsibility, but that he was an enthusiastic proponent and participant of it. The following year, 1942, would account for almost half the total Jewish deaths in the Holocaust all by itself.

Hitler portrait crop.jpg
By Bundesarchiv, Bild 183-H1216-0500-002 / CC-BY-SA, CC BY-SA 3.0 de, Link

As mentioned in:

The Final Solution — Sabaton

September 3, 1941 — Zyklon B is first used at Auschwitz

One of the deadliest chemicals ever invented, Zyklon B is a derivative of Prussic acid. It was invented in 1922 by a small team of German chemists led by Nobel Prize winning chemist Fritz Haber, whose previous creations included mustard gas and other chemicals of warfare used in World War One.

In 1941, the gas was first deployed in three death camps: Auschwitz-Birkenau, and Majdanek, and Sachsenhausen. Its first large scale use was one September 3, when 600 Russian POWs, 250 Polish POWs and 10 criminals were killed at Auschwitz-Birkenau. Some of the victims survived more than 24 hours of exposure to the gas – when this was discovered, additional quantities of it were pumped into the killing chambers. By the time the war ended, an estimated 1.2 million people were killed with Zyklon B, most of whom (960,000) were Jews.

Birkenau a group of Jews walking towards the gas chambers and crematoria.jpg
By anonymous, possibly SS photographers E. Hoffmann & B. Walter – Auschwitz Album ([https://collections.ushmm.org/search/catalog/pa8538 record in USHMM collection), Public Domain, Link

As mentioned in:

Point of No Return — Immortal Technique

September 15, 1935 — The Nuremberg Laws are passed by the Reichstag

Unanimously passed by the Reichstag on the evening of September 15, 1935, the Nuremberg Laws were the first legal codification of Nazi anti-Semitism. There were two laws: the Law for the Protection of German Blood and German Honour, which prohibited marriages and extramarital intercourse between “Jews” and “Germans” and also the employment of “German” females under forty-five in Jewish households; and The Reich Citizenship Law, declared those not of German blood to be Staatsangehörige (state subjects) while those classified as “Aryans” were Reichsbürger (citizens of the Reich). In effect, this second law stripped Jews of German citizenship.

In addition, the laws contained a codification of who was considered to be Jewish, defined by how many grandparents one had who were Jewish or German. There were four statuses under the law, of which two were considered Jewish and two German. A later expansion of the law extended its provisions to Gypsies and Negroes. These laws remained in effect until the German surrender, nearly ten years later.

RGBL I 1935 S 1145.jpg
By Herausgegeben vom Reichsministerium des Innern – Reichsgesetzblatt I 1935 S. 1145, Public Domain, Link

As mentioned in:

Mrs. O — The Dresden Dolls