Germany stages a false flag; called the Gleiwitz Incident it gives Germany a justification to invade Poland, which it does on 1 September, starting the Second World War (on the German side; Britain and France would not declare war on Germany until 3 September and they would not take part in any significant military land offensive for another eight months; known as the Phoney War in English and Sitzkrieg in German, this was very convenient for Germany and her allies as it allowed them easy domination).

On 17 January 1940 Polish code breakers crack the Luftwaffe's Enigma code allowing the Allies to intercept and read Germany's air force's messages.

In May the Phoney War would end and henceforth the world was at war once more.

On Sunday 7 December 1941 at 7:55am local time, Japan bombs Pearl Harbor causing major damage to the American naval fleet, many deaths and injuries. On the following day, President Roosevelt gave his Infamy Speech ('Yesterday, December 7, 1941, a date which will live in infamy, ...') and declares war on Japan. On 11 December Germany and Italy declare war on the United States of America and shortly after America would be on the European front of the war.

On 22 June Germany begins Operation Barbarossa, the invasion of the Soviet Union, which breaks the non-aggression pact between the Soviet Union and Germany. This immediately changed the dynamic of the war - and its map.

Ford Motor Vehicles hires women for the first time -- Ford believed women should not work -- and like the other car manufacturers, starts building for the war effort (instead of cars). This, of course, is because the United States was now very much a part of the war.

On 20 January the Wannseekonferenz (Wannsee Conference) takes place in Germany; this conference worked out the details of the Final Solution of the Jewish Question including deciding what constitutes a Jew (in relation to the Holocaust), essentially leading to the next part of the Holocaust (the extermination camps led by the SS was not the first phase).

Rationing -- shoes, sugar, meat, coffee, canned foods, consumer goods and fuel -- begins on the American home front.

On the European front there are several revolts in some of the concentration camps and even the extermination camps Treblinka and Sobibór.

Operation Overlord (D-Day, 6 June) -- which significantly changes the course of the war -- begins. It would succeed due in part to the success of the deception of the Nazis by the Allied Operation Fortitude - including inflatable tanks and buildings cleverly used with deceptive messages, as well as lack of preparedness on the German side.

Several hundred Jews would on 7 October take part in an uprising in the death camp Auschwitz-Birkenau even disabling one of the crematoriums (gas chambers and ovens) entirely.

Germany would stage its last major offensive; known as the Unternehmen Wacht am Rhein ('Operation Watch on the Rhine') on the German side and the Ardennes Offensive to the Allies: more commonly this is the Battle of the Bulge.

On 30 April (10 days after Hitler's 56th birthday), Adolf Hitler and his newly wed wife Eva Braun commit suicide; Berlin surrenders on 2 May; Nazi Germany surrenders and VE Day (Victory in Europe) is declared 8 May; Hiroshima ('Little Boy', 6 August), Nagasaki ('Fat Man', 9 August) bombed; Soviet Union declares war on Japan and on 12 August, Emperor Shōwa (Hirohito) orders the immediate surrender of Japan (a coup d'état was foiled).

People, places and things mentioned in the letters and how they relate to the those writing and receiving the letters.