On the eleventh hour....

...of the eleventh day of the eleventh month. In 1918, at this time, the guns of the Western Front fell silent for the first time in four years. 

 In Flanders Fields

In Flanders fields the poppies blow
Between the crosses, row on row,
   That mark our place; and in the sky
   The larks, still bravely singing, fly
Scarce heard amid the guns below.

We are the Dead. Short days ago
We lived, felt dawn, saw sunset glow,
   Loved and were loved, and now we lie,
In Flanders fields.

Take up our quarrel with the foe:
To you from failing hands we throw
   The torch; be yours to hold it high.
   If ye break faith with us who die
We shall not sleep, though poppies grow
In Flanders fields.

John McCrae, MD (1872-1918)
Canadian Army

After reading this poem an American, Moira Michael, wrote another poem, We Shall Keep the Faith, which is credited with starting the tradition of wearing a poppy.

Oh! You who sleep in Flanders’ fields,
Sleep sweet – to rise anew;
We caught the torch you threw;
And holding high we kept
The faith with those who died.
We cherish, too, the Poppy red
That grows on fields where valour led.
It seems to signal to the skies
That blood of heroes never dies,
But lends a lustre to the red
Of the flower that blooms above the dead
In Flanders’ Fields.
And now the torch and poppy red
Wear in honour of our dead
Fear not that ye have died for naught
We’ve learned the lesson that ye taught
In Flanders’ Fields.

The history of the poppy.