3 sept. 1939 - Britain and France declare war on Germany

Description:

Two days after Germany's invasion of Poland, Britain and France officially declared war. Before Germany invaded, both Britain and France promised to protect Poland's borders. British suffered many casualties, but this day marked the beginning of the end of the Third Reich.

https://www.telegraph.co.uk/history/world-war-two/6128589/Second-World-War-The-day-the-balloon-went-up.html