Picture the first winter of World War I. British and German soldiers are freezing in muddy trenches, sometimes close enough to shout across to each other. Late on Christmas Eve 1914, the British troops heard the Germans singing carols and saw lanterns and little fir trees lined up along the enemy trenches. Men started calling back and forth. On Christmas Day, soldiers from both sides climbed out and met in No Man’s Land. They swapped gifts, took pictures together, buried their dead, and in some spots even kicked a football around. It didn’t happen everywhere, and the fighting started back up, but for a few hours the men who were supposed to kill each other stood side by side as human beings.