Ten million dead and 20 million injured — with famines, regional conflicts and the Spanish flu claiming a further 40 million bodies — by the end of the Great War, Europe was demographically and morally decimated.

“Europe is a vast tomb. The legacy of the war has taken a far greater toll on the morale of the people than the economy,” historian Jean-Yves Le Naour told AFP. “Contrary to 1944-45, when there was hope in the future, in a new world, in 1919 society was paralyzed under the weight of the dead.”

With three million war widows and six million orphans, Europe was gripped by an “immense period of mourning,” said Annette Becker, a specialist on the period.

“In France, in particular, which experienced some of the worst casualties, we can estimate that between two-thirds and three-quarters of French society were directly or indirectly bereaved,” she said. “The extent of personal tragedy had no historical parallel — all these deaths of young people, violent deaths with unprecedented mutilations.”

A less publicized aspect of the post-war world were the efforts by governments to suppress overt signs of mourning, which were seen as a “betrayal” of those who had gloriously sacrificed themselves in battle.

Mourning was made all the more difficult by the disappointment that came with the aftermath of the war. The return of peace brought few benefits for those who had fought, while the losers felt “tremendous hatred and frustration over the terms of the peace treaty, that ultimately created the framework for World War II,” said Becker.

The body counts among the more than 70 million who fought were appalling. On average, 900 French and 1,200 Germans were killed every day between 1914 and 1918.

Those who survived often returned with stark and permanent reminders of the horrors they had witnessed.

Amputated, maimed, blinded, gassed: the mutilations of millions were visible to all, clear symbols of the awful new technologies that had appeared on the battlefield — machine guns, shells, flamethrowers and poison gas.

Despite aid efforts — France created a national lottery specifically to finance help for the “broken faces” — many of these lonely, disabled figures ended up begging on the streets.

Many others wound up in asylums, with up to half of survivors thought to have suffered some level of mental trauma.

In the early years of the war, such problems were made all the more insufferable by society’s lack of understanding. It was not until 1915-16 that the reality of psychological trauma began to be taken seriously by doctors.

“Against a backdrop of patriotic fervor, madness was always suspected to be an attempt to escape one’s duty,” Becker said.

Recent research has finally shone some light on the extent of the damage done.

Around 600,000 German soldiers are now known to have been treated for psychological disturbance during the war. In France, some 20,000 hospital beds — 15 percent of the total — were reserved for such cases. Britain handed out 65,000 special pensions for the traumatized.

Twenty years later, there were still at least 4,000 French veterans in asylums, still living through the horrors of the unprecedented barbarity they had witnessed.