Halloween has its origins in the ancient Celtic festival of Samhain (pronounced "sah-win").
The festival celebrated the end of the harvest season in ancient Gaelic culture.
The pagan Gaelic people believed that on October 31, the boundaries between the worlds of the living and the dead overlapped
and the deceased would come back to life and cause havoc such as sickness or damaged crops.
Irish and Scottish immigrants carried the tradition of celebration with to North America in the nineteenth century.
Based on the popularity of "Trick & Treat" in North America, the custom has spread throughout the world.