1. German Invasion of Poland (September 1, 1939):
- Nazi Germany launched a surprise attack on Poland, utilizing its blitzkrieg (lightning war) strategy, which combined rapid armored and mechanized forces with air power.
- The invasion marked the official start of World War II.
- Britain and France declared war on Germany in response to its aggression.
2. Non-Aggression Pact (August 23, 1939):
- Prior to the invasion of Poland, Germany and the Soviet Union signed the Molotov-Ribbentrop Pact, a non-aggression agreement that secretly divided Poland and other territories in Eastern Europe between the two powers.
- This agreement allowed Germany to proceed with its invasion without immediate Soviet interference.
3. Fall of Poland (September 28, 1939):
- Despite fierce resistance, Poland was quickly overwhelmed by the German military, which advanced deep into Polish territory.
- Warsaw, the Polish capital, fell on September 27, and the Polish government went into exile.
- The Soviet Union also invaded eastern Poland on September 17, effectively dividing Poland between Germany and the Soviet Union.
4. Battle of the Atlantic Begins:
- The Battle of the Atlantic, one of the most prolonged campaigns in military history, began with both German and British naval forces engaging in a struggle to control the Atlantic Ocean.
- German U-boats (submarines) sought to disrupt British supply lines, while the British deployed convoys and anti-submarine measures to protect their trade routes.
5. Phony War or "Sitzkrieg" (September 1939 - April 1940):
- Following the fall of Poland, a period of relative calm ensued on the Western Front. This phase of the war was marked by a lack of significant military activity, giving rise to the term "Phony War" or "Sitzkrieg" (Sitting War).
- The Allies and Germany engaged in limited skirmishes along the border, but there were no major confrontations.
6. Soviet Invasion of Finland (November 30, 1939):
- In response to Finnish resistance to territorial demands, the Soviet Union invaded Finland, beginning the Winter War.
- Although outnumbered and outgunned, the Finns mounted a fierce defense, inflicting heavy losses on the Soviet army.
7. German Invasion of Denmark and Norway (April 9, 1940):
- Germany launched a surprise attack on Denmark and Norway, aiming to secure strategic naval bases and access to vital resources.
- Denmark was swiftly occupied, while Norway resisted fiercely, leading to a prolonged campaign.
8. Fall of France (June 22, 1940):
- Germany launched Operation Fall Rot, a decisive offensive against France, Belgium, Luxembourg, and the Netherlands.
- German forces employed their blitzkrieg tactics, advancing rapidly through the Ardennes Forest and splitting Allied defenses.
- French troops were defeated, and the French government signed an armistice on June 22, effectively ending France's participation in the war.
9. Evacuation of Dunkirk (May 26 - June 4, 1940):
- In the face of the German advance, British and Allied troops found themselves trapped in Dunkirk, France.
- A massive evacuation operation was launched, with over 330,000 troops successfully evacuated back to Britain, despite heavy aerial bombardment by German forces.
The early weeks of World War II set the stage for the global conflict that followed, with Germany making significant territorial gains in Europe and the war expanding to various fronts. The United States would later enter the conflict after the Japanese attack on Pearl Harbor in December 1941.