What was the final spark that ignited the “european powder keg” and started world war 1

The event that set off World War I was the assassination of Archduke Franz Ferdinand of the Austro-Hungarian Empire and his wife Sophie by Gavrilo Princip, a Serbian nationalist, on June 28, 1914 in Sarajevo.

hello there the answer is a

sorry if i am wrong hope that : )

on the morning of  july 21,  1861, general mcdowell ordered the  unionarmy to attack. it was on this hill that  confederate  colonel thomas jackson and his forces held back theunion  troops.