The first time I ever became aware of World War One's significance was thanks to this book:
It's the final book in the Anne of Green Gables series and focuses on her youngest daughter. If you didn't cry reading this book, you are dead inside [SPOILER] Walter! Sob![/SPOILER].
The other way I learned about The Great War was thanks to my sophomore year high school history teacher (who was THE BOMB basically why I'm a history major). He had this exercise for the class. We were all broken into five groups/countries. We needed to appoint an ambassador and various government officials. We had a fact sheet on our country. Here's the twist - only our ambassador could communicate with other countries. There were rounds where we got updates on what was going on. We'd have to huddle with our ambassador and give him/her instructions. At the end of class, my country, Freedonia, was part of a tripartite treaty against two other countries then our teacher informed us that we had missed the whole point and had started a world war. So mutual defense treaties are bad mmmmkay?
At UMass Amherst, I took an amazing course about World War I. The textbook was so good, I never bothered selling it back. The Treaty of Versailles chapter just gave me chills. You know how hindsight is 20/20? Now we know the reparations and punishments against Germany fanned a rage and nationalism that lead to another world war. Apparently back in 1918, ambassadors and leaders knew how vindictive the treaty was. Ferdinand Foch said, "This is not a peace. It is an armistice for twenty years." World War Two started in 1938.
So, how are we doing now? Well, we have NATO and a growing nationalist, right wing, xenophobic movement gaining ground in Europe. It seems like Germany is sane and stable now. Russia looks like it wants to be the new/old Germany. The EU is simultaneously unifying and also pissing people off. The European economic recovery hasn't really stabilized (I blame austerity). It is my hope Europe is old enough and tired enough just to sit out and complain during the next war. They'll let the new kids annihilate themselves.