What Aztec ceremony was held at the end of each 52-year calendar cycle?

The Aztec ceremony held at the end of each 52-year calendar cycle was the New Fire ceremony.

Known as the Binding of the Years, the ceremony marked the completion of a calendar round: the point when the 260-day ritual calendar and 365-day solar calendar returned to the same combination. This occurred every 18,980 days, or 52 solar years. Aztecs feared that the sun might fail to rise and that the existing world could end if the cycle was not renewed.

Before the ceremony, fires throughout the realm were extinguished. Priests traveled to Huixachtlan, also called the Hill of the Star, where they watched the heavens. A new sacred fire was kindled using a fire drill, traditionally on the chest of a sacrificed captive, and runners carried the flame to temples and household hearths.

New Fire was not an ordinary annual festival. Festivals such as Toxcatl and Tlacaxipehualiztli belonged to the regular 18-month ritual year, whereas New Fire renewed the much longer calendar round.