The job of a film director is extremely challenging which requires the person to have knowledge of almost all the fields of film production. The success or failure of a film more or less depends on the capabilities of a film director.
On September 1, 1939, Hitler invaded Poland from the west; two days later, France and Britain declared war on Germany, beginning World War II. On September 17, Soviet troops invaded Poland from the east.
But if you think about it, WW2 started on different dates for all countries. 1931 was the official start of the war for Japan who invaded Manchuria. 1935 was the official start of the war for Italy who invaded Ethiopia. September 1, 1939 was the official start date of the war for Germany who invaded Poland.