Of the many legends in relation to Mid-Autumn Festival, the story of Chang Er flying to the moon 嫦娥奔月 (cháng é bēn yuè) is the most well-known.
It is said that in ancient times there existed ten suns and the extreme heat made people's lives very difficult, ruining crops and drying rivers. A young hero named Hou Yi with his godly archery skills, shot down nine of the suns. As a reward the queen of heaven granted Hou Yi an elixir that would make him immortal. Hou Yi did not drink it as he did not want to part with his loving wife Chang Er and gave it to her for safekeeping.
One day when Hou Yi was out hunting, Peng Meng who was jealous of Hou Yi and harboured evil intent, demanded that Chang Er give him the elixir. Knowing the consequences of the elixir falling into the wrong hands, she drank the potion. With that Chang Er flew up to the moon and become a goddess. Chang Er's great love for her husband drew her to the moon because it was the closest to earth from heaven. Since then, grief stricken Hou Yi would present Chang Er’s favourite foods to the moon as an offering to her.
Upon hearing of Chang Er‘s sacrifice and becoming a goddess, the people began to worship Chang Er as well. They would pray to her for peace and good luck. Since then, the custom of worshipping the moon became a common ritual during the Mid-Autumn Festival.
Watch the YouTube clip below for an animated story of Chang Er in Mandarin.
Interesting fact cited on Wikipedia: Chang Er was mentioned in a conversation between Houston Capcom and the Apollo 11 crew just before the first Moon landing in 1969:
Houston: Among the large headlines concerning Apollo this morning, is one asking that you watch for a lovely girl with a big rabbit. An ancient legend says a beautiful Chinese girl called Chang-O has been living there for 4,000 years. It seems she was banished to the Moon because she stole the pill of immortality from her husband. You might also look for her companion, a large Chinese rabbit, who is easy to spot since he is always standing on his hind feet in the shade of a cinnamon tree. The name of the rabbit is not reported.
Michael Collins: Okay. We'll keep a close eye out for the bunny girl.