World War II has been a favorite subject of Hollywood since 1940, before the U.S. even entered the fighting. But the industry has been less interested in World War I, aka The Great War or The War to End All Wars (as it was sadly/optimistically dubbed).

In the past 25 years, there have been 16 best-picture Oscar nominees set during WWII. In those same years, there was only one set in World War I: Steven Spielberg’s “War Horse.” This is just one of many reasons why Universal-DreamWorks’ “1917,” a strong Oscar contender this year, seems so remarkable.

Krysty Wilson-Cairns, who co-wrote “1917” with director Sam Mendes, says she’s not surprised filmmakers have gravitated to the later war. “The Second World War was about countries uniting to fight the tyranny of the Nazis; it seemed like the only option to save humanity. But with the First World War, the motivations are obscure. It was partly for profiteering, partly because empires were starting to lose their stakes abroad.”

There are other reasons why the second war is covered more. It’s easier to research, via conversations with survivors, as well as books, newsreels and many other sources. In contrast, there are no living survivors of World War I. Wilson-Cairns adds, “I couldn’t research online; I had to go to the Imperial War Museum and to France, and find books out of print for decades.”

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Over the years, Oscar voters awarded best picture to eight films about World War II: “Mrs. Miniver,” “Casablanca,” “The Best Years of Our Lives,” “From Here to Eternity,” “The Bridge on the River Kwai,” “Patton,” “Schindler’s List” and “The English Patient.” (WWII also figured in such winners as “The Sound of Music” and “The King’s Speech.”)

In addition, there have been a slew of WWII films nominated for best picture, ranging from “The Great Dictator” (1940) to “Darkest Hour” and “Dunkirk” (both 2017). And Hollywood has cranked out hundreds of lesser films centering on various aspects of the war.

Though there have been significantly fewer World War I movies, they tend to be top quality. Best-picture winners include “Wings,” “All Quiet on the Western Front” and “Lawrence of Arabia,” while other Oscar nominees include “Sergeant York,” “A Farewell to Arms” and the French-language “Grand Illusion” (1938).

Some brilliant films didn’t earn Academy recognition, including Stanley Kubrick’s “Paths of Glory,” Peter Weir’s “Gallipoli” and two greats that were ineligible for different reasons, King Vidor’s 1925 “The Big Parade” and Peter Jackson’s 2018 documentary, “They Shall Not Grow Old.”

It’s surprising that WWI is so under-served, because it was so significant. It was the first war featuring airplane fighting, machine guns and nerve gas; in other words, it was the birth of modern warfare. And the repercussions were long-lasting. An estimated 16 million died; genocides and the Spanish influenza killed an additional 50 million-100 million. And the cease-fire of 1918 left many things unresolved that erupted again in the World War II.

For research, Wilson-Cairns went to the area in France depicted in the film. “When I was there, I realized something I had read but never understood: that men died so their country could gain inches, just inches of land.”

It’s difficult to tell stories about this war in a way that’s engaging or inspiring, but Mendes found the key in tales of his grandfather Alfred Mendes. Though much attention has been paid to the amazing technical achievements of the film and its immersive experience, “1917” really works because of the immersive emotions. It’s one from the heart.