Militarism led to WWl by other countries not being able to prepare for war. Some countries were way ahead and were prepared for war. This led to a powerful and unfair war.
Alliances were a cause of WWl because multiple countries were coming together to fight and become more powerful. Other countries didn't like this, so they went to war to tell everyone to fight on their own.
Imperialism was a cause because of the want for more land. They wanted to expand their territory by using Imperialism to become stronger.
Nationalism was a cause because people were judging people about where they were from. They fought for their rights and their countries fought for them.
The Assassination of Archduke Franz Ferdinand, also known as the spark. He was murdered by Garvrito Princip who was a member of the black hand terrorist group on June 28, 1914.