Folklore refers to traditional beliefs, customs, and stories passed down through oral tradition in a cultural group. Folktales are popular stories passed down orally from generation to generation, including fables, fairy tales, and urban legends. Fairy tales are a subgenre of folklore that include magical or supernatural elements and a predictable structure, though they do not necessarily feature fairies. The Brothers Grimm collected and published many European folktales and fairy tales that had been part of oral tradition. Dragons feature prominently in the myths and folklore of many cultures around the world.