Greetings! This is certainly a question which has popped up before on AH, and one which speaks volume about the overall "uniqueness" (though I use that term with some caution) of the War To End All Wars in both popular history and the academic historiography. Discourse around the First World War (especially regarding its causes) has persisted ever since the war ended in 1918, and it is unlikely that we shall ever be able to answer the question of "Why did World War I start?" with a definitive response in the next century or so. This response is less of a deep-dive into that historiography and more of a whirlwind tour of some aspects of the First World War which mark it out as the Seminal Tragedy of the 20th century. Let's begin.

Note: my research mainly centers around the origins of the First World War and its diplomatic history, as opposed to the experiences of those who lived (and possibly served) during it. More can definitely be said regarding the "tragic" aspect there, so fellow AH travelers are welcome to add their own tuppence on the matter!

The Bigger Picture

"The changes in our own world have altered our perspective on the events of 1914. In the 1960s-80s, a kind of period charm accumulated in popular awareness around the events of 1914. It was east to imagine the disaster of Europe's 'last summer' as an Edwardian costume drama. The effete rituals and gaudy uniforms, the 'ornamentalism' of a world still largely organized around hereditary monarchy had a distancing effect on present-day recollections."

- Historian Christopher Clark

The sentiment echoed in Clark's prose above gives us a good starting point for the first reason why the First World War is remembered as such a tragedy. To be certain, all wars are tragedies, and the First World War is by no means "more tragic" than any other war simply by virtue of it being just a bit more "unique". What makes the First World War stand out within the larger narrative of the 'short twentieth century', as Eric Hobsbawm termed it, was its impact on the period as a whole. It was of course, not the war to end all wars, nor did its conclusion make Europe a more peaceful continent. In school curricula and a fair bit of the academic historiography, the other tragedies of the 20th century can be traced back (in some way or another) to a lingering consequence of the 1914-1918 conflict.

The constant fascination with World War I has been in part spurred by historians and the general public looking to the events of that war to understand their current situations in the 20th century. From political agendas to historical discourse, the Great War of the 20th century has been memorialized, studied, and mythologized (amongst other narrative-twisting processes) by those societies and individuals who viewed their situation as a consequence of the Treaty of Versailles (and by extension, the war as a whole).

Of course, we should not be so dismissive of historical agency to attest that the First World War is "unique" because it directly led to the Second World War and everything else tragic in the past 100 years. Instead, it would be more appropriate to note that the "tragedy" of 1914 has been amplified as a result of the other tragedies which (to varying degrees) have stemmed from the post-war order of 1918.

The Tragedy of 1914

“The lamps are going out all over Europe, we shall not see them lit again in our lifetime.”

- British Foreign Secretary Sir Edward Grey, on the eve of war in August 1914

The popular quote above is a nice transition from the previous point to this historiography-heavy one. The First World War as a historical event is rather tragic because it took place at a time when such a war seemed to be a product of the past. Now of course there had been European conflicts between 1900 and 1914, most notably two Balkan Wars and several flare-ups in Morocco (one in 1905-06 and another in 1911), but 1914 seemed to be a year in which the continent was stabilising itself from the recent turbulence.

For many statesmen and civilians, the 20th century seemed to promise the dawn of humanity's triumph and "enlightenment". This understandably Hegelian (or Whig) outlook on the direction of civilization was evident in the Exposition Universelle of 1900. For more on that event and the general attitude at the turn of the century, this previous Saturday Showcase entry should be of some interest. Margaret MacMillan also notes this in the introduction to her work on the outbreak of war in 1914:

"The coming of war took most Europeans by surprise and their initial reaction was disbelief and shock. They had grown used to peace; the century since the end of the Napoleonic Wars had been the most peaceful one Europe had known since the Roman Empire. True there had been wars, but these had been far-off colonial ones like the Zulu wars in southern Africa, on the periphery of Europe like the Crimean War, or short and decisive like the Franco-Prussian War."

The sheer speed with which the war broke out and escalated also remains a topic of debate within historiography. Why did the shooting of an archduke in Sarajevo plant the seeds of various casus belli that dragged in all the great powers of Europe? Thirty-seven days is all it took from Gavrilo Princip's first shot to the beginnings of a conflict which would mobilise 65 million troops, claim three empires, witness the deaths of 20 million civilian and military casualties, and wound another 21 million.

Over the years there have been a slew of historiographical discussions regarding the true "perpetrator(s)" of the seminal tragedy. Fritz Fischer and various other German historians in the 1960s reignited the debate by arguing that the German Empire was to blame for the conflict. Their writings were analysed and rebuffed by other historians who argued instead for all manner of alternatives, shifting the "blame game" from a 'collective European fault' to 'Serbian pan-Slavism'. Recently the historiography has again shifted to focus on Austro-Hungarian policies at the turn of the 20th century and Balkan geopolitics as a key lens to view the events of 1914. As I remark in that Saturday Showcase feature, reductionist teachings which you might encounter in school or in textbooks do a severe disservice to the work of these historians:

"When shots rang out in Sarajevo and killed the heir apparent to the Austro-Hungarian throne, they rang out in a world beset with a litany of factors which, despite none of them being a key casus belli, presented the leaders of Europe with a geopolitical situation where much was at stake. The militaristic war plans and naval arms race were not turned to as the first option; though the decision to call forth the reserves and pack the troop trains was one which helped the dominoes to fall quicker than they might have had in previous years, but they alone cannot explain how an entire continent marched off to the front."

Thus, World War I is "unique" as a conflict from the international relations and geopolitics because of how incredibly rapid the situation deteriorated from a political assassination to an entire continental war. Alongside that of course, we must also remember the human cost of the war, as this was indeed a war fought in ways which the world had never seen before.

Hope this response helps, and feel free to ask any follow-ups as you see fit.

Sources

Clark, Christopher. The Sleepwalkers: How Europe Went to War in 1914. New York: Penguin Books, 2012.

Howard, Michael. The First World War: A Very Short Introduction. Very Short Introductions. Oxford: Oxford University Press, 2007.

MacMillan, Margaret. The War That Ended Peace: How Europe Abandoned Peace for the First World War. London: Profile Books Ltd., 2014.