Humans have always been using their imagination to escape from their tedious or gloomy routine into wondrous worlds filled with fascinating creatures, magical potions and spells, lush landscapes, romantic castles and cottages, and heroic figures fighting all sorts of evils, from malevolent witches, to abstract anomalies, to gigantic monsters. Whether in books or on screen, fairy tales have played an essential role in those escapades, and here are the key elements that define them: a beginning with a set phrase like “Once upon a time” that introduces the main characters; the protagonist’s quest, mission, or desire that sets the action; magical tools, creatures, and/or realms, like fairies, wizards, unicorns, or a hidden dimension; a villain with great power and ambition; seemingly insurmountable obstacles; and a usually satisfying denouement.