The generally accepted beginning and end dates for WW2 are: 1 Sept 1939 to 2 Sept 1945.
The British and the French following an appeasement policy thought that if they satisfied Hitler's political ambitions, they could avoid war. So, they allowed Hitler to annex the Sudetenland (part of Czechoslovakia, with mostly German inhabitants). Soon Hitler occupied the all Czechoslovakia in 1939. (Before that Austria was annexed too in the Anschluss, in 1938). There was nobody who opposed Hitler's ambitions. And he knew taht. However, after Hitler occupied the whole of Czechoslovakia, Britain and France replaced the appeasement policy by guarantees to Romania, Greece and Poland. Consequently, when Hitler invaded Poland (1 Sept), Britain and France declared war on Germany (3 Sept). (Unfortunalely that was just a declaration, but no armies were sent to hel the Polish - this period was called the 'phoney war'. )
The attack at Pearl Harbor was on US territory, and the target was the United States Navy. The attack brought the US into WW2, which made it a truly GLOBAL war.
Germany invaded Poland on Sept. 1, 1939 and started WW II.
None were invaded in the military 'invasion' sense prior to 1938. Austria was absorbed voluntarily into Greater Germany. The Munich pact that involved France and Britain allowed Germany to take over portions of Czechoslovakia in 1938. Possibly it could be called 'invasion' in that in latter 1938 Germany did take over most the non-Munich portions of Bohemia and Slovakia - placing them under 'protectorate status', similar to the multitude of colonies 'protected' by France, Russia and Britain. In addition to Germany, Hungary and Poland also sliced off small parts of Slovakia for themselves. Germany did not really invade any nation until Sept. 1, 1939 when the war with Poland began. Germany in this regard was late to the game since Poland, Italy, Japan and Russia had all increased their respective territories prior to Germany by direct invasion of neighbors or colonies.
September 1, 1939
Hitler invaded Poland from the West, on Sept 1st, 1939. On Sept 17, 1939the Soviets invaded Poland from the East.
German suprise attack on Poland 01 Sept 1939
German suprise attack on Poland 01 Sept 1939
Sept 3rd 1939 was a Sunday.
The allies tried to stop Germany by signing an agreement with Hitler.
The Axis powers deliberately launched unprovoked attacks on other coutries who were then forced to defend themselves. Michael Montagne Britain and France allowed Germany an almost free hand until Sept. 1, 1939 when Hitler crossed into Poland claiming Germany had been attacked by Poland. Britain and France could no longer stand by as they had a mutual defence treaty with Poland. They declaired war on Sept.3 1939.
The Soviets moved into Eastern Poland Sept 17, 1939. It was 17 days after the Germans attacked the western part.
Sept 01, 1939 to Sept 02, 1945
It was a Friday.
In March 1938 Hitler bloodlessly took over Austria and later in 1938 he bullied the German inhabited Sudetenland of his neighbor Czechoslovakia. In Sept. 1938 the Western European powers betrayed Czechoslovakia to Germany when they gave the Sudetenland to Germany. They hoped this would bring peace. Six months later in March of 1939 Hitler invaded Czechoslovakia.
The six steps to war that Hitler did were: First one: Re-arm in October 1933. Second one:Re-militarize Rhineland in March 1936. Third one: Austria in March 1938. Fourth one: Sudetenland in September 1938. Fifth one: Czechoslovakia in March 1939. Sixth one: Poland. Pact August 1939, invasion 1/Sept/1939, declare war 1/Sept/1939. Then it started the Second War World.