The Day of the Dead celebrations in Mexico can be traced back to the indigenous Olmec, Zapotec, Mixtec, Mexican or Aztec, Maya, P'urhépecha, and Totonac. Rituals celebrating the deaths of ancestors have been observed by these civilizations perhaps for as long as 2500–3000 years.[1] In the pre-Hispanic era, it was common to keep skulls as trophies and display them during the rituals to symbolize death and rebirth.