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.

2686-2181 bce-- "egyptian civilization developed along the nile river in large part because the river’s annual flooding ensured reliable, rich soil for growing crops."

1069-664 bce-- "ancient egyptians developed wide-reaching trade networks along the nile, in the red sea, and in the near east."