This is Veterans Day in the U.S., Remembrance Day in Britain and the Commonwealth.

It originally was meant to give thought and tribute to those men killed in the First World War, the greatest disaster to befall Europe since, perhaps, the Black Death of the 15th century.

The Second World War is better remembered and chronicled, especially in the U.S., because the U.S. was much more deeply involved in the latter, and because it had far more civilian casualties.

But the First World War was more damaging in that it nearly destroyed a generation of young men, in Europe, and ended an era of growth and confidence in Britain and on the continent. It set the stage for the Second World War, far bloodier because of the civilian casualties — perhaps made possible because so much of society had grown inured to the notions of killing on an industrial scale, learned in the trenches of the First World War.

Why is November 11 a holiday in much of the world? Because that is the day the First World War ended, in 1918.

Britons and Canadians, in particular, wear a red poppy for several days before November 11. Every soccer game over the weekend began after a minute of silence.

It is good that a day is set aside for this. But beginning on August 1 or next year, we will be looking at World War I centennials for nearly five years, the length of what was known for two decades as the Great War.

The First World War began on July 28, 1914, and ended on the 11th hour of the 11th day of the 11th month of 1918, with the collapse of four empires (German, Russian, Austro-Hungarian and Ottoman).

The 100-year anniversaries for those gloomy days is less than a year away.

If anyone cares to, some fairly shocking 100-year anniversaries could be generated for nearly every day of the war’s duration.

It was felt with particular pain in France and Britain, where something like a quarter of all men from certain age cohorts (1890-1899) were killed with many others maimed. Some cities were particularly hard hit, including English towns like Accrington, where the Accrington Pals were killed by the hundreds in the first hour of the Battle of the Somme in 1916.

Every town in France and England has a monument to the dead of the First World War, and without exception the list of names is far longer for the first war than those added on, a generation later, for the second.

The 1914-1918 war took such a toll in those two countries that they were willing to make concession after concession to Hitler and the Nazis, in the 1930s, in the vain hope of avoiding another war. Many Germans at that time were keen to rewrite history, not liking how the First World War turned out (with the punitive Treaty of Versailles after it).

The First World War, then, was a turning point in the history of the human race. It could be argued, a turn for the worse.

Certainly, very little was gained for the near ruin of Western Civilization.

If we can remember November 11, then we need to be ready for nearly five years of memorials coming up.