What is it like for people on two sides of a line to put aside differences and join united, even if for a short time? The story of the Christmas truce in World War I is something many have grown up hearing, though no one know for sure exactly how it happened. Sainsbury, a British department store reenacted the story for a their Christmas ad. In the process of creating the ad, they did some extensive research on the story and how it came about. You can watch the full ad below.