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. In the pre-Hispanic era, it was common to keep skulls as trophies and displaythem during the rituals to symbolize death and rebirth.
The festival that became the modern Day of the Dead fell in the ninth month of the Aztec calendar, about the beginning of August, and was celebrated for an entire month. The festivities were dedicated to the goddess Mictecacihuatl, known as the "Lady of the Dead," corresponding to the modern Catrina.
In most regions of Mexico, November 1honors children and infants, whereas deceased adults are honored on November 2. This is indicated by generally referring to November 1 mainly as "Día de los Inocentes" (Day of the Innocents) but also as "Día de los Angelitos" (Day of the Little Angels) and November 2 as "Día de los Muertos" or "Día de los Difuntos" (Day of the Dead). 
Families tidying and decorating graves at acemetery in Almoloya del Río in the State of Mexico.
Detail of an "Ofrenda" in Ciudad Universitaria, México.
Many people believe that during the Day of the Dead, it is easier for the souls of the departed to visit the living. People go to cemeteries to communicate with the souls of the departed, and build private altars, containing the favorite foods and beverages, as well as photos andmemorabilia, of the departed. The intent is to encourage visits by the souls, so that the souls will hear the prayers and the comments of the living directed to them. Celebrations can take a humorous tone, as celebrants remember funny events and anecdotes about the departed.
Plans for the day are made throughout the year, including gathering the goods to be offered to the dead. During the two-dayperiod, families usually clean and decorate graves; most visit the cemeteries where their loved ones are buried and decorate their graves with ofrendas (offerings), which often include orange marigolds called "cempasúchitl" (originally named cempoalxochitl, Nahuatl for "twenty (i.e., many) flowers"). In modern Mexico, this name is sometimes replaced with the term "Flor de Muerto" ("Flower of theDead"). These flowers are thought to attract souls of the dead to the offerings.
Catrinas, one of the most popular figures of the Day of the Dead celebrations in Mexico
• The altars
Some families build altars or small shrines in their homes; these usually have the Christian cross, statues or pictures of the Blessed Virgin Mary, pictures of deceased relatives and other persons, scores ofcandles and an other stuffs to offer. Traditionally, families spend some time around the altar, praying and telling anecdotes about the deceased. In some locations, celebrants wear shells on their clothing, so that when they dance, the noise will wake up the dead; some will also dress up as the deceased.
• School altars
Public schools at all levels build altars with ofrendas, usually omitting thereligious symbols. Government offices usually have at least a small altar, as this holiday is seen as important to the Mexican heritage.
Those with a distinctive talent for writing sometimes create short poems, called "calaveras" ("skulls"), mocking epitaphs of friends, describing interesting habits and attitudes or funny anecdotes.
A common symbol of the holiday is the skull (colloquiallycalled calavera), which celebrants represent in masks, called calacas (colloquial term for "skeleton"), and foods such as sugar or chocolate skulls, which are inscribed with the name of the recipient on the forehead. Sugar skulls are gifts that can be given to both the living and the dead. Other holiday foods include dead bread (pan de muerto), a sweet egg bread made in various shapes, from plain...