This Christmas is the 90th anniversary of the World War I truce when British troops took on the Germans at football.
Trench warfare had only just begun in 1914
The soldiers sang Christmas carols before leaving their trenches to play a match in sub-zero temperatures in no-man's land near Armentieres, France.
The Germans won 3-2, according to some soldiers, and the truce gradually came to an end in the same way it had begun - by mutual consent.
A film inspired by the events entitled Merry Christmas is being planned.
The truce came about during the first winter of the war - not yet dubbed the "Great War".
Around 40,000 Britons had lost their lives by that stage - a tiny number compared to the body count by 1918.
The British soldiers on the Frelinghien-Houplines sector on the western front were the main allied participants in the Christmas festivities.
French and Belgian troops, who were fighting in the same trenches as the British, were less willing to take part.
By Christmas 1914 they had already lost 400,000 people and parts of both their countries were occupied.
The truce began when German soldiers started to sing Christmas carols.
British troops responded and gradually both sets of soldiers moved out of their trenches and met in no-man's land.
After exchanging stories and gifts, several games of football broke out.
The only result recorded was a 3-2 victory by the Germans, quoted in soldiers' letters from both sides.
On some parts of the front hostilities were officially resumed on Boxing Day at 0830 - ceremonial pistol shots marking the occasion.
In other areas non-aggressive behaviour lasted for days and, in some cases, weeks.
Military historian Andrew Robertshaw says such a truce would have been unthinkable a year later.
He said: "This was before the poisoned gas, before aerial bombardment.
"By the end of 1915 both sides were far too bitter for this to happen again."