This Aztec holiday continues today
Day of the Dead is one of the oldest celebrations currently in existence. Although it is often described as "Mexican Halloween," the only real connection between the two holidays is a coincidence of timing.
Celebrated mainly in Mexico, Dia de Muertos falls on November 1st and 2nd. It coincides with the Catholic holiday All Saint's Day, although it predates Catholicism by several thousand years. Dia de Muertos is a festive, brightly colored celebration of the dead in which people honor and remember their ancestors, as well as providing offerings for their spirits. In many regions, children and babies are honored on November 1st, and adults are honored on November 2nd.
The roots of Dia de Muertos go back to the Aztec civilization. The Aztecs celebrated the deaths of their ancestors at the beginning of August, for an entire month. (No one ever accused the Aztecs of half-assing anything.) Unlike today, the offerings and sacrifices were mainly dedicated to an Aztec goddess of the dead.
In the wake of the Hispanic invasion, the Aztec holiday was moved to November 1st in order to placate the sensibilities of the new Catholic rulers, and merge the religions. (A similar phenomena took place when the birth of Christ was scheduled to overlap with the existing midwinter festivals of pagans and heathens throughout Europe.) This remapping was a natural fit, since the Catholic celebration of All Saint's Day also involves going to cemeteries and lighting candles to remember the dead.
A species of orange Mexican marigolds (Tagetes erecta) are closely associated with Dia de Muertos, because they are believed to attract the spirits of the dead. These marigolds are arranged around the offerings,
The beautiful sugar skulls sold for the celebration are left out as offerings for the dead, along with other food, snacks, toys for the spirits of dead children, and pillows so that the dead can have a comfortable place to sit. These offerings are gathered at cemeteries, as well as at small altars in homes and in public spaces. Most public schools and government offices set out an altar for Dia de Muertos.
Dia de Muertos celebrations also happen to coincide with the return of the Monarch butterfly to Mexico. These orange and black beauties flock to their Mexican wintering grounds in the hundreds of thousands. They are believed to represent the souls of the dead, returning home to visit with their families for one or two days a year.