I teach my students a simple quote that is easy to remember that covers the four underlying causes of World War I in Europe:
"I want your land, I'm better than you, I've got guns and I've got friends"
I want your land - Imperialism - the competition between six European empires for control of the world's colonies and resources.
I'm better than you - Nationalism -the hyperpatriotism that existed in each of these six empires prior to the war
I've got guns - the arms race between the six countries to produce massive military machines, with millions of soldiers and huge navies
I've got friends - the system of alliances that these empires cooperated under, which gave them an overconfidence in their ability to win the war, and dragged them into it once it started.
You might also find it interesting to look at the Eastern front of the war since the Western front is what gets most of the attention in most history classes. There were absolutely incredible battles in the Alps between Slovenia and Italy, the battle at Gallipoli (subject in part of one of Mel Gibosn's first movies) and some really incredible history that most people don't know a great deal about.
There is such a wealth of really fascinating history out there about the war, I am sure you won't have any trouble finding an area that is of interest to you, whether it is a particular geographic area, a technological area, or a political one.
I think that you will probably find the topic fascinating with the more research and analysis you uncover. There are a variety of reasons as to why the war started, and in analyzing them, a greater understanding of what motivates much in way of conflict emerges. There is the nationalism element that is present, the forging of secret alliances, and the desire to protect autonomy while acting upon it. Yet, there are other reasons such as the growth of science and technology as well as the fear of a dwindling economic base. These reasons and the ideas they possess help to explore much in way of the start of World War I as well as other conflicts that are global in scope, but sadly human in many ways.
It started because Gavrilo Princip assassinated the Archduke Franz Ferdinand of Austria-Hungary. But that was just the immediate cause. There was lots of stuff going on to make Europe get to the point where a spark like that could set off a war.
- Nationalism and ethnic solidarity were causing people like the Slavs to not want to be ruled by Germans, for example. This is why Princip did what he did.
- Militarism was making countries glorify war and think it could improve them.
- Alliances bound the countries together (partly based on ethnic solidarity) and made a big war more likely.
- Competition for power -- Germany wanted to be stronger than it had been and other countries felt threatened and did not want to lose power.