The Western Front
Poland was defeated rapidly because of the German´s Blitzkriet* method or warfare.
The next six months are called the Phoney war because nothing happened. France and Britain were waiting forHitler´s next move and he was waiting to see if they would make peace, so the Germans planned an offensive in the west.
In April Germany invaded Denmark and Norway.
In May Germany conquered Holland, Belgium, Luxembourg and France. German troops marched into Paris and took direct control of most of the country. The government ruled by General Petain escaped to the south (Vichy) trying to govern but under Hitler´s supervision (puppet government).
After this, in Britain nthe Prime Minister Chamberlain was replaced by Winston Churchill (1940).
Because of the superiority of the English Navy, Germany's first plan of attack was to destroy the RAF by attacking the British Air Force before Germany could cross the English Channel. This plan led to the Battle of Britain (August and September 1940) and Britain won the Battle.
Now the Germans decided to bomb British cities. They hoped to break British morale and force the government to make peace.
Never in the field of human conflict was so much owed by so many to so few.