The killing of Franz Ferdinand in 1914 was the spark that led to the start of World War 1. After the killing things went down hill very fast as country’s started to declare war everywhere as Austria-Hungary declared war on Serbia and all their alliances started to join in. In my Explain Everything that I made it explains why the killing of Franz Ferdinand was the spark of World War 1 and what country’s where involved in the war.

https://youtu.be/epWGb-rilHU