El Día de los Muertos (the Day of the Dead) is sort of a merger between an ancient Aztec festival held for the goddess of the underworld, and the Catholic practice of honoring saints without their own feast days on Nov. 1 (All Saints' Day) and all of the faithful departed on Nov. 2 (All Souls' Day). The latter custom was brought to Mexico by Spanish conquistadors [source: DeNinno].
During the two-day Day of the Dead party, which is Mexico's largest annual celebration and a national holiday to boot, the focus is all about remembering loved ones who have passed on. On Nov. 1, deceased children are remembered, while on Nov. 2 it is the adults' turn. In some places, the festival begins on Oct. 31, because the belief is that young children's souls arise at midnight.
During these days, people will build altars in their homes (or at a public site) dedicated to the departed, as well as clean and decorate the graves of loved ones. They'll also place gifts at gravesites and family altars, like candy skulls or chocolates, small trinkets, food, drink and marigolds, the flower Mexicans associate with death [source: DeNinno]. Parties and parades, where people dress up as skeletons, are also part of the commemorations. The dead, Mexicans believe, would want to enjoy the same kinds of activities they did in life. The holiday is not only celebrated in Mexico, but also throughout Latin America and Latino communities in the U.S.A. [source: National Geographic].