The Day of the Dead, known in Spanish as Día de los Muertos, is a holiday that celebrates life and honors the dead through traditions, food, decorations, and activities intended to sustain the connections between the living and the dead. The Day of the Dead originated in Mexico and is celebrated around the world, beginning on the last days of October and concluding in early November, contrary to the singular "day" implied by its name. While some recognize this celebration as a time of playful skeletons, colorful papel picados ("perforated paper"), and candlelit graveyards, it has been observed in some form throughout Mexico for over 3000 years, and its traditions are as varied as the people who celebrate it.

In her book Celebrating Latino Folklore: An Encyclopedia of Cultural Traditions, María Herrera-Sobek writes that "The Day of the Dead marks the one time during the year when the dead may return, if only for a few hours, to visit their loved ones and to enjoy the pleasures they had known in life" (403). Festivities often begin on the evening of 31 October and conclude on 2 November, but some rural communities in Mexico begin their observance as early as 27 October, when those deceased without families or friends can find sustenance for their souls in the form of crusts of bread and water vessels hung outside of homes. In these communities, even the unknown are not forgotten.

On the next day, celebrants accommodate the souls of those who died violent deaths, and who might be viewed as malevolent spirits:

These fears stem from Aztec beliefs that the quality of our afterlives is dictated by the manner in which we die, not the manner in which we lived. For this reason, those souls who died by accident, murder, or other violent means are offered sustenance at a safe distance.

(Herrera-Sobek, 404)

30 and 31 October mark the days when communities commemorate and welcome back the souls of children, those who died before being baptized and after baptism, respectively. On 1 November, the souls of the adult dead are welcomed back by their families. These loved ones, sometimes known as the 'Faithful Dead', are welcomed back with ringing church bells and home ofrendas, where their family members await. During the days of the festival, families tend to the gravesites of their loved ones. Celebrants clean, repair, and decorate graves, bring and share food, light candles, and sometimes play or enjoy music in the cemeteries. The festivities conclude at dusk on 2 November, when the dead still lingering among the living make their way back to the afterlife, sometimes with the aid of masked 'mummers' tasked with frightening away the souls who might dawdle in the world of the living.

During each day of the celebration, as souls are welcomed, the living create ofrendas, where they display food, flowers, and visual art, often including scenes or iconography with skulls and skeletons, to help them connect with and provide sustenance for the souls of the dead.

An ofrenda, meaning "offering" in Spanish, is a unique and prominent part of the Day of the Dead celebrations. Assembled by all able members of the family, ofrendas are usually made on a table or platform, though some are tiered and resemble a step pyramid, and are traditionally covered with a decorative cloth. Once the surface is covered, family members begin carefully arranging the structure's namesakes, the offerings.

What is ultimately placed on an ofrenda depends entirely on the people assembling it and those deceased souls to whom the offerings are given, but most ofrendas include food, water, candles, and colorful tissue paper garlands known as papel picados. Other objects on an ofrenda might include flowers, photographs of the deceased, statues of saints, prayer cards, sweets, and other mementos of importance to the dead. The journey from the afterlife to the realm of the living is generally viewed as long and tiring, so some families include personal cleaning items such as soap, combs, razors, and toothbrushes on their ofrenda, so that the souls of the deceased can refresh themselves on their arrival. Moreover, ofrendas that commemorate the souls of children might include new toys, milk, or clothing, while the offerings arranged for the souls of adults might include favorite alcoholic beverages and other objects that reflect the preferences of the deceased in life. In addition to the objects placed on the offering tables, some ofrendas will have a woven mat laid in front to give the souls a place to rest when they arrive. In some cases, families construct an arch—decorated with flowers, hanging food items, or palm leaves—over their ofrenda.

Ofrendas might also include a cross among the assembled objects. These crosses might represent the pan-Mexican idea of the Tree of Life. According to these beliefs, the tree supports the sky and creates a sort of pathway connecting the three levels of the world: "the starry arch of heaven, the stony Middleworld of earth made to flower and bear fruit by the blood of kings, and the dark waters of the Underworld below" (Haley & Fukuda 2004, 135). With this in mind, the ofrenda table itself represents a microcosm of the world, with the tabletop representing the world of the living, where offerings are presented, the floor representing the underworld, where the dead can rest, and the arch representing the sky, which stretches over all else.

According to Herrera-Sobek, a traditional ofrenda contains components symbolic of the four elements. Earth can be represented by crops, including corn, which played a significant role in Mesoamerican culture and history, particularly for the Maya, the P'urhepecha, and the Aztec civilization. Air can be represented on the ofrenda by the artfully crafted tissue paper of papel picado, which predates the Spanish conquest and was originally an Aztec art form. Traditionally made by skilled artisans cutting intricate patterns, images, or scenes into up to 50 sheets of tissue paper at a time, papel picado are used for a wide variety of celebrations throughout Mexico, with their colors and designs made to fit different occasions. The papel picado created for Day of the Dead typically includes images of ofrendas, religious symbols, and skeletons or skulls engaged in various activities. Made from brightly colored, light-weight, delicate paper, the lace-like banners are hung in front of ofrendas so that they can be subject to the motion of the air.

Water and fire are very literally represented on the Day of the Dead offering tables. Families leave water in decorative containers to quench the thirst of the returning souls after their long journey. More religious celebrants might even incorporate holy water into their ofrendas. As for fire, families traditionally light candles for each soul the offerings commemorate. The candles represent hope and faith and are left lit throughout the night on the ofrenda so that none of the returning souls of the dead are left in darkness.

The creation of ofrendas, and especially the inclusion of food on these offering tables, is based on the Indigenous Mexican belief that, even after death, souls require sustenance. To fill this need for the nourishment of the deceased, Day of the Dead festivities include a number of different foods. Corn, mentioned above, is harvested in October and used to make tamales and gorditas, which are often joined on the ofrenda by moles, breads, seasonal fruits, and vegetables.

One bread in particular, pan de muertos ("bread of the dead"), is specific to the holiday. This special sweetbread is traditionally made with orange water, anise seeds, and nutmeg, and is dusted with sugar. It is usually shaped as a round, flat bun topped with two strips of dough shaped like bones and forming a cross, but it can also be shaped like a person, an animal, or a heart, an organ that figured prominently in the beliefs of the Aztec inhabitants of prehispanic Mesoamerica.

By far the most iconic food item made for the Day of the Dead are decorated sugar skulls or calaveras de azucar. Made from granulated sugar and meringue powder and allowed to harden, these sweet treats are often decorated with festively colored icings, tin foil, and sequins and have become an increasingly popular symbol of the holiday. This bounty of food is one of the principal means by which the living connect with the souls returning from the afterlife. Mexican people do not believe that the food on the ofrendas is actually consumed by the souls of the dead. Instead, the food is indicative of the connection between the deceased and those who love and remember them. For the dead, as for the living, the preparation is a labor of love. After the dead return to the afterlife, the food put out in their honor becomes an offering to the community present for the festivities. In this way, the nourishment made to sustain the weary souls of the dead helps to strengthen and maintain connections among the living.

Flowers are another of the many objects used as a decorative element in celebrations of the Day of the Dead. Symbolizing the brevity of life, flor de muertos lend their beauty and fragrance to the festivities, and a few types of flowers are particularly prevalent during this holiday. The most recognizable of these is the marigold. Marigold flowers were known to the Aztec civilization as cempoaxochitl, deriving from the Nahuatl words cemposalli, meaning "twenty," and xochitl, meaning "flower." Thus, the term roughly translates to "flower of twenty petals" or "twenty flower." Herrera-Sobek refers to it as "the flower of 400 lives" and mentions a Nahua belief that the marigold had been a gift from the sun god Tonatiuh for the purpose of honoring the dead. Brightly colored and fragrant, marigolds are traditionally believed to help lead the souls of the dead, who are said to have a keen sense of smell, to the offerings prepared for their arrival. Some communities scatter marigold petals to form a path within their homes between the front door and the ofrenda, or, in smaller villages, paths leading to the cemeteries to help the dead return to the afterlife following the festivities.

While marigolds are the most ubiquitously associated with the holiday, some orchid species in the genus Laelia, including L. autumnales, L. albida, and L. gouldiana are native to Mexico and have been used in Day of the Dead ceremonies for centuries. According to the Smithsonian Gardens Orchid Collection, this role has led to their cultivation by locals and the acquisition of names like "calaverite", lily of all saints, flower of the dead, and flower of the souls for specific Laelia species.

Skeleton imagery and iconography figure prominently in urban celebrations of the Day of the Dead, though it is not as prominent in rural Mexican festivities. Sometimes called calacas, the skeletons that cavort through the Day of the Dead appear in everything from costumes and candy to toys, window dressing, and print media. While they might seem macabre, they are depicted with a whimsical tone and in a way that casts the faults and the frailty of human existence in a more cheerful light. The calacas serve as reminders that death is an inevitable part of life, not something to be feared or worshipped. It is likely that the modern ubiquity of calacas in Day of the Dead celebrations can be attributed to the work of José Guadalupe Posada (1852 to 1913), who pioneered depictions of luxuriously dressed skeletons in action in the afterlife with the satirical, darkly whimsical tone that informs the active skeletons in modern iterations of the Day of the Dead. His art was originally commissioned to illustrate print articles called calaveras (meaning "skulls" in Spanish) that were critical of the Mexican elite and government of the day.

Skeletal imagery, however, was commonplace in the civilizations of Mesoamerica before the arrival of the Spanish. Several of the gods in Maya religion, Zapotec belief, and Aztec religion, including the Aztec god Mictlantecuhtli, whose name roughly translates to "Underworld (Mictlan) Lord (tecuhtli)", are depicted as animate skeletons. Moreover, these gods were not singularly regarded with the dread and trepidation often associated with chthonic deities. According to Mary Miller and Karl Taube, they were regarded with a mixture of fear and derision, capable of ruthlessness and cunning but also frequently tricked or outwitted by other gods and mortals alike in the extant mythologies. Miller and Taube even describe Mictlantecuhtli as being "fundamentally stupid and vulnerable to the tricks of smarter gods" (113). It is possible that some strand of this sensibility informs modern depictions of skeletal figures in Day of the Dead celebrations.

That being said, the Day of the Dead figures are meant to mock death as a concept, not the deceased. It is rare to see calacas or other humorous iconography near those sitting vigil during the day and at night during this holiday. The humor of these depictions appears largely in public and anonymous contexts, not in the private ceremonies dedicated to departed loved ones. The exuberant skeletons that have become so deeply associated with the Day of the Dead on a surface level only represent one facet of the holiday. The depictions of skeletons and skulls during the Day of the Dead are seasonal, secular, satirical, commercial, and designed for the living, but they do not take the place of celebrants actually mourning and honoring their deceased relatives.

While the conversion efforts and legacy of the Spanish in Mesoamerica are exceedingly complex, there is evidence that some Indigenous holidays were purposefully rescheduled to be compatible with Catholic Christian holy days after Spanish missionaries arrived in South America. Through this process of calendrical recontextualization, it is possible that the Day of the Dead, like so many Indigenous traditions, became subject to syncretism in the meeting of the multitudinous Mesoamerican and Spanish cultures. The Florentine Codex, written in the mid-16th century by a Franciscan friar named Bernardino de Sahagún, records two Aztec feast days, Miccailhuitontli ("Feast of the Little Dead Ones") and Miccailhuitl ("Feast of the Adult Dead"), which were known together as Tlaxochimaco ("The Offering of Flowers") or Xocotl uetzii ("Fruit Falls"). These were held during the ninth and tenth months of the year according to the Aztec calendar and were moved to coincide with Catholic observance of All Souls' Day and All Saints' Day.

Ironically, the Spanish priests’ attempts to identify common ground in order to replace Indigenous beliefs with those of Catholicism may have played an active role in preserving those same traditions. It is important to bear in mind that, however, that it is not possible to clearly define the ideas that informed and influenced this holiday over such a long period of time. Beliefs about death that abounded in Mesoamerican cultures before the conquest introduced entirely different, but at times highly compatible, ideologies, and any or all of these could have played a role in shaping the festivities in Mexico in late autumn.

Among the Indigenous peoples of Mesoamerica, some believed that humans could die three deaths. The first was the death of the physical body, the second was the death of the spirit when, in some capacity, life returned to its origins, interred in the earth or ascending to the sun. The third death, and the one that was truly a source of fear, was the death of the soul, the termination of self when there was no one left alive to remember the individual, or to welcome them back to the world of the living. The ceremonies and customs of the Day of the Dead are a means to avert this final death for ancestors and the recently deceased alike.