What was the underlying cause of World War One

What was the underlying cause of World War One?
In World War One there were three major causes. In the beginning the Europeans wanted balanced power, but then alliances began to form. The assassination of Archduke Franz Ferdinand sparked an immediate outbreak of war. However, there are numerous causes of the world war that are commonly known as; alliance systems, militarism, and imperialism.
One of the underlying causes is the alliance system. Europeans wanted balanced power throughout the world, therefore making all major countries to become equal. Slowly but surely many countries began to divide and two large alliances were formed. Specifically the Triple Alliance included; Germany, Austria-Hungary, and Italy.