The War in Europe began in September 1939, when Nazi Germany under Adolf Hitler invaded Poland.
Using blitzkrieg tactics, the country was quickly overtaken.
The world was shocked.
Britain and France responded by declaring war on Germany but took little action.
This became known as the Phony War.
But in 1940, German offensives rapidly defeated Denmark, Norway, Belgium, the Netherlands and France.
The British Army meanwhile was on the retreat being evacuated from Dunkirk.
Britain alone was attacked by Germany during the battle of Britain and the Blitz.
However, the Luftwaffe failed to defeat the RAF.
In June 1941, Hitler invaded Russia under the Codename Operation Barbarossa.
