Is this a multiple choice question? What are the events? Next time list them so that someone can help you with the question.
It would depend on which civil war you are referring to.
it was the 2nd world war
The attack of Pearl harbor and then the united states got word of what hitler was doing to the Jews and so we invaded
The Assassination of Archduke Franz Ferdinand of Austria triggered the start of the Great War (World War I)
The incident that triggered the beginning of World War 1 was the assassination of the heir to the Austro-Hungarian throne.
the great depression triggered WWI
Japan attacking the US in a battle called PEARL HARBOR
Archduke Ferdinand
Invasion of poland
invasion of poland
World War I, World War II, and the moon landing are major world events.