What is the origin of Mid-Autumn Festival?

Ghost Festival, also known as Zhongyuan Festival, originated from Buddhist bonsai. According to legend, before Sakyamuni's disciple Mulian Venerable became a monk, his parents died and he missed his mother very much. After getting the word, he opened his eyes and found his mother in hell. I found that his mother had fallen into the hungry ghost road, and the food entrance turned into a flame. Hunger was too bitter. Unable to save her mother, Manglietia asked the Buddha for advice to save her mother. The Buddha was moved by Manglietia's filial piety and awarded him the orchid flowerpot Buddhist Sutra.

According to the instructions, Master Mulian and monks saved their mother by providing food and vegetarian food to all beings in hell on the 15th day of the seventh lunar month. So Buddhists have a grand "bonsai" every year, which is what we call "Ghost Festival".