Apparently, the Germans first decorated their trenches with Christmas trees, and belting out Christmas carols – the first/main one is thought to have been ‘Stille Nacht’ (Silent Night). This prompted some (English) carol singing from the British side. This led to more singing, coming out of their trenches and meeting and conversing with one another, exchanging of gifts (whiskey, cigars, chocolate, etc.), sharing a Communion Service together (!), helping one another bury their dead, football (‘soccer’) games, and various other acts of kindness.
It’s a tremendous story, and it’s worth your time reading some of the letters from the troops describing the events.
May peace rule our hearts!