In Aztec mythology, Mictecacihuatl is Queen of Mictlan, the underworld. Her role is to keep watch over the bones of the dead. She presided over the ancient festivals of the dead, which evolved from Aztec traditions into the modern Day of the Dead after synthesis with Spanish cultural traditions. She is said now to preside over the contemporary festival as well. Mictecacihuatl was represented with a defleshed body and with jaw agape to swallow the stars during the day.
The backs of the monuments often are flat. The boulders were brought from the Sierra de los Tuxtlas mountains it is thought that the monuments represent portraits of powerful individual Olmec rulers. Each of the known examples has a distinctive headdress. The heads were variously arranged in lines or groups at major Olmec centres, but the method and logistics used to transport the stone to these sites remain unclear.