China has a tradition that we need to eat moon cake at Mid-autumn festival, which means the harmony of a family. At that day, all the members of family should come together, and sit there to enjoy the good moment with people who they love.
There is a story. Long time ago, there was ten suns in the sky, which caused huge damages to people, like burn the plant, burn the field, and even people was suffering. Fortunately, a hero popped up, named Yi, he shot nine of them and rescue the people. Since his accomplishment, a very beautiful woman married to him, they lived in a perfect life. However, someday, that a Taoist give him a package of medicine, if you eat half, you will never die, if you eat the whole thing, you will go to another place and become angel. For some reason, his wife ate the whole package, and went to the moon, so Yi want commemorate his wife, he ate the moon cake in the certain day of the year. And then it becomes a tradition.