It’s a giant mess, and that explains a lot
The usual explanations for the causes of World War I — alliances and imperialism — can be confusing because they stop well short of the full set of conditions that led up to the sudden outbreak of war in Summer 1914.
It always sounded strange to me, probably because like most people in this day and age, and until I started digging into this on my own over the last couple of years, I had no real concept of the level of European chaos and conflict — especially the ruling class vs the ruled, and between ethnic groups — that fed a constant system of discontent for centuries, creating a powder keg ready to erupt at any time.
One of the biggest players in the late 19th century was the Austro-Hungarian Empire, which also serves as a good example of the kind of ever-present ethnic and tribal conflict and ruling class power struggles that has always defined Europe.
Keep in mind, this was known as the “civilized” world.
Austro-Hungarian Empire 1848 - 1922
Layered on top of that, this mess of international alliances and protection of global imperialist interests.
The First World War and International Relations 1900 - 1920