The Imagination of the End of the World in Ancient Greece thought : the end of a world and the end of the world, two myths with mirror effects. Since the beginning of greek literature, myths of a world temporary ending in fire and/or water and its consequences on human history emerged, whereas the first texts about the mythical theme of the radical end of the world appeared around the II nd s. B. C. How to explain the gap between these two myths which develop similar motives (like, for instance, islands disappearing and grounds engulfing, cosmic conflagration or concertinaing of times), and have mirror effects to the extent that the first one makes humanity move from a mythical to an historical time, whereas the second one makes humanity move from the historical era to an everlasting world, somehow mythical? The answer is perhaps to be found in influences exerted by eastern religious and mythical thought on the greek ones. Those oriental sources can mainly explain how greek thought, during the hellenistic period, endorsed an a priori unaccustomed idea: the theme of the radical ending of the world. These sources can explain how this idea gave birth to texts written in greek langage that gained increasing popularity in particular with the beginnings of christianity, texts in which originated the beginnings of millenarism and which inspired a lof of irrational behaviours.