Every 52 years, when the Aztec calendar round completed its cycle, all fires across the empire were extinguished. In total darkness, priests climbed Huixachtlan hill and watched for the Pleiades to cross the zenith at midnight. If they passed, the world would continue. A new fire was kindled in the opened chest of a sacrificial victim, then carried by runners to every temple and household. The last pre-Columbian ceremony was in 1507.