Once every 52 years, Aztec priests let the fire die out. The high priest, wearing a turquoise mask representing Xiuhtecuhtli, would then perform a Xiuhtlalpilli, or "new fire ceremony", which ...

On a hill where Aztec priests once studied the stars, President Manuel Avila Camacho of Mexico dedicated a great modern observatory. Tonanzintla, near Puebla, 70 miles southeast of Mexico City ...