The Day of the Dead, a holiday celebrated primarily in Mexico, is similar to Halloween in that both holidays occur back to back, both are rooted in festivals held by ancient peoples, both focus on death and both are celebrated with traditional foods.
While Halloween is celebrated on Oct. 31 each year, the Day of the Dead is celebrated on Nov. 1, allowing people to celebrate both holidays. The Day of the Dead is rooted in the ancient Aztec Festival of the Dead, a two-month-long harvest festival in which people honored the dead. Halloween originally began in Ireland as Samhain, a Celtic harvest festival during which it was believed that the threshold between the worlds of the living and the dead was flexible and easily passed through. When Christianity came to Ireland, Samhain became celebrated as All Saints Day, which honors saints and those who have died recently, as does The Day of the Dead, with the night before celebrated as All Hallows Eve, the source of the word "Halloween."
The Halloween tradition of dressing up in costumes comes from the Celtic belief that the dead would be out and about on that night, and that the best way to fool them was to dress in costume. Halloween is often celebrated with portrayals of the dead in various macabre forms, as compared to the Day of the Dead, in which people visit cemeteries and decorate graves to encourage the recently dead to come back for a visit. Both holidays decorate with skeletons and other images of the dead. On the Day of the Dead, families leave food on graves for their dead loved ones, while on Halloween, people hand out candy at their front doors to visitors who are still living.