Day of the Dead is a Mexican holiday that is celebrated in Mexico and around the world in other cultures. The holiday focuses on gatherings of family and friends to pray for and remember those who have died. It is particularly celebrated in Mexico, where the day is a bank holiday. The celebration takes place on November 1 and 2, in connection with the Catholic holidays of All Saints Day and All Souls Day. Traditions connected with the holiday including building private altars honoring the deceased using sugar skulls, marigolds and the favorite foods and beverages of the departed and vising graves with these as gifts. They also have possessions of the deceased.
The visit to the cemeteries is to encourage visits by the souls, so the soulds will hear the prayers and the comments of the living directed to them. Celebrations can take a humorous tone as people 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 three day period, families usually clean and decorate graves, visit the cemeteries where their loved ones are buried and decorate the graves with offerings which include orange Mexican marigolds. These flowers are thought to attract souls of the dead to the offerings.
Toys are brought for dead children and bottles of tequila, mezcal or pulque or jars of atole are brought for adults. Families will offer trinkets or the deceased favorite candies on the grave. Offerings are put in homes, usually with foods such as candied pumpkins, pan de muerto, sugar skulls and beverages. The offerings are left out in the homes as a welcoming gesture for the deceased. Pillows and blankets are left out so the deceased can rest after their long journey.
In the Southern California area, there are celebrations of Dia de los Muertos at Hollywood Forever Cemetery, Olvera Street and Old Town in San Diego. I am sure there are others, but these are the ones I have been to and know about.