What were the causes of wold war I

There were many things that led up to to WW1 but the main thing that started WW1 was the assassination of Archduke Ferdinand.

The war started mainly because of four aspects: Militarism, Alliances, Imperialism and Nationalism. This is because big armies become potential threats to other countries, other countries started forcing alliances in order to secure land ... The overall cause of World War was the assassination of Archduke Franz Ferdinand.