Question: what were the major events leading to an allied victory?
Answer: 1939: Hitler invades Poland. Hitler's invasion of Poland on 1st September 1939 marked the beginning of WW2 in Europe.
1940 (1): Rationing. ... 
1940 (2): Blitzkrieg. ... 
1940 (3): Churchill Becomes Prime Minister. ... 
1940 (4): Evacuation of Dunkirk. ... 
1940 (5): Battle of Britain. ... 
1941 (1): Operation Barbarossa. ... 
1941 (2): The Blitz.