Conversation so far:
what was the premise of world war 1
World War I began in 1914 after the assassination of Archduke Franz Ferdinand and lasted until 1918.
how did the assassination of archduke franz ferdinand lead to world war 1
The assassination of Archduke Ferdinand was the spark that caused Austria-Hungary to strike the first blow and all the European powers quickly fell in line to defend their alliances.
how many people died in world war 1
The total number of military and civilian casualties in World War I is estimated to be about 40 million.
was world war 1 necessary
World War I has been called unnecessary because the original dispute that triggered the conflict was limited, yet it triggered a massive, global war.

Question: how did the war lead to world war 2
Self-contained rewrite: how did the world war 1 lead to world war 2