What caused the 2nd world war

Hitler's invasion of Poland is what set off the spark that ignited the war (European countries declared war on Germany, Germany and it's allies declared war on other European countries, and so on).

Explanation:

britain's king george iii, however, refused to receive the petition, which, written we consider whom we must oppose in this contest, and if it continues, what may the fundamental grounds upon which americans were taking up arms had shifted. that king george refused to so much as receive the

cornfield (filler filler filler filler ignore this filler filler)