A Quiet Continent
The European Union is an ambitious project. 28 states, 510 million people and the world's third largest economy didn't come easy. It formed in spite of centuries of mutual enmity. One only has to skim the table of contents of a history book to know that Europeans absolutely loved to go to war with one another. Well, that's a bit of a misnomer - European royalty absolutely loved to go to war with one another. The commoners didn't have much of a say in it.
The story of why the European Union came to be first goes back to the Peace of Westphalia in 1648, which gave exclusive dominion of a royal or ecclesiastical sovereign over his possessions. This became the foundation for nation-states as we know them today. For instance, the French king couldn't force English serfs to pray his way, and Swedish armies couldn't force "contributions" from cities that were not Swedish. With borders now solidified, monarchs were able to focus more on building up their own administrations to better tax and develop their subjects. Each nation had its own story from then on, but they all collided in World War One.
The stage for the tragedy of World War One had Germany, Austria-Hungary, and the Ottoman Empire against Great Britain, France and Russia in the worst conflict in human history up until that point. The condensed carnage on the Western Front in particular is the stuff of legend and horror, exacerbated by the necessity to pour more men into the meat-grinder in order to have those already killed and maimed to not have done so in vain. When the end of the war came, the losers suffered enormously - Austria-Hungary was shattered into multiple nation-states, the victorious British and French Empires carved up the Ottoman Empire, and Germany was burdened with an incredibly harsh war debt. How each of these nations were treated after the war would end up haunting Europe in their own way
The fragmentation of Austria-Hungary was done with the idea that each nation (group of people) should have their own state (government, land, cities, resources). Austria-Hungary not only included the Germanic Austrians and Hungarians, it also included Croats, Serbs, Slovenes, Italians and Saxons. The problem with this is that centuries of trade and migration put entire communities of a nation deep within a different state. When the borders were made, there was a distinct feeling of otherness for those on the wrong side. Ethnic cleansing became a byproduct of nation-states as each government tried to solidify its control on the country by getting rid of potential traitors. This was a concern because the new nations bickered with each other almost instantly about where the lines were drawn, citing borders from hundreds of years ago and treaties made under duress. This ethnic conflict was not localized to the Balkans - the fall of the Russian Empire lead to Poles, Ukrainians, Lithuanians, and Russians also frantically scrambling for land and wealth in the vacuum created by the absence of both Russian and German hegemony, and under the auspices of national sovereignty and the nation state Poland attempted to conquer Eastern Europe. They did not succeed, but Poland's actions serve as a warning - years of subjugation and oppression do not take away a people's ability or desire to oppress.
Ethnic strife also happened in the former Ottoman Empire. The swapping of populations between Greece and Turkey lead to the deaths of thousands and the displacement of tens of thousands. This does not touch upon the Armenian genocide that Turkey denies happened to this day, an ordeal caused by Ottoman fears of Russia invading over the Caucuses and receiving support from Armenians. Turkey itself was almost carved up by the British, French and Italians after the Treaty of Sevres, but the Turkish War of Independence under Kamal Ataturk restored Turkish control over all of Anatolia and much of Kurdistan and Armenia. More long-term was the British and French control over the Levant - France controlling modern-day Syria and Lebanon, Britain controlling Egypt, Palestine and Iraq. It was these colonial divisions that made the basis for nations in the region today, and they were not done for the benefit of the locals.
The most consequential was the effect of exorbitant war debt on Germany. Desperate to pay off their debt and avoid further French occupation of western Germany, the German central bank enacted a series of policies that caused hyperinflation. What was intended to make paying off the debts easier ended up causing a total economic collapse, causing further social upheaval for an already demoralized and frantic populace terrified of Communist uprisings and foreign invasion. It was in this chaos that the National Socialist Party seized opportunity - led by decorated war veteran and skilled orator Adolf Hitler, the National Socialist Party would incrementally gain seats in the German parliament until it became the largest party by plurality in government. Seizing another opportunity through crisis, the Nazis (as National Socialists game to be known as) were able to wrest control of many important government posts from President Hindenburg after the Reichstag Fire in 1932, leading to an incrementally more fascist state in Germany.
The Second World War that followed devastated Europe once more. But while the Western Front of the First World War was generally localized to a twenty-mile stretch of land, the Second World War brought the war to home. Aerial bombings leveled cities of repute - Antwerp, Dresden, Coventry, Bremen, among many others. The carnage unleashed on civilians is mind-numbing, and if you are truly curious to see what war looks like, it is only a Google search away. But you won't have to deal with the smells, the sounds, or the emotional attachment to the people trapped in rubble as a firestorm broils the flesh from their bones.
This continental trauma was something that survivors understandably wanted to prevent from happening again. Unfortunately, the Cold War made that seem unlikely. Security worries lead to the formation of the American-led NATO and Soviet-led Warsaw Pact, coinciding with a military buildup along the Iron Curtain in Central Europe. If war would come again, it might make Europe and the northern hemisphere in general uninhabitable. In the shadow of apocalyptic war, the founding pillars of the European Union planted themselves in Western Europe. What began as an organization to make a common market for coal and steel production in West Germany, France, the Netherlands, and Belgium. Italy and Luxembourg laid the foundation for similar international organizations meant to give common direction for Western Europe.
After the Iron Curtain fell, the Maastricht Treaty bound together these organizations and member nations into the European Union. Such a union soon showed itself to be imperfect, as can only be expected - different nations with hundreds of years enmity and different legal codes were bound to have disagreements over the power of government bodies in relation to supranational bodies. Subsequent amendments were made to the Maastricht Treaty, the most important being the Treaty of Lisbon. Regardless, the European Union proved itself valuable - the common market afforded to its members increased trade and free travel gave citizens opportunity to travel and study as they wished.
Not all saw the value equally. Britain in particular flexed its old anti-continental attitude, such as haranguing Polish immigrants for being plumbers. Russia was extremely concerned with the gradual eastward spread of the European Union, acting against its strategic prerogative to have as much allied land between Germany and Moscow as possible. Resentment grew in Greece as economic policies put forth by Germany benefited German industries and banks dis-proportionally. Germany's prominence in the European Union has led to the European Union being satirically called the Fourth Reich. Considering Germany's importance as the financial and industrial core of the European Union, this isn't that far off the mark. Talks of the necessity of a European Army are gaining in momentum as America's commitment to NATO (and by extension, protecting the European Union) seemingly wavers, driving more Euroskeptics into fearful frenzy of tyranny from Brussels.
The future of the European Union is in question. Upcoming elections in France and the Netherlands risk to tear vital members away from the Union, and democratic institutions encouraged by the Union are losing integrity in the east. The ethnic strife displayed in the collapse of the Austria-Hungarian and Ottoman empires lays dormant but alive, awaiting the opportunity for bloodshed. Peace on the continent hinges on the next couple of years, for if the Union disintegrates, the continent will undergo the most significant loss of community since the Roman Empire. You learned the period after that time as the Dark Ages, it would be unfortunate to have another one.