Halloween has its origins in ancient Celtic harvest festivals and traditions surrounding death. On October 31st, the Celts believed the boundary between the living and the dead became blurred and spirits of the dead would wander the earth. Today, Halloween is celebrated in many countries with traditions like carving jack-o'-lanterns from pumpkins, children dressing in costumes and going door-to-door asking for candy, and telling scary stories. The traditions and celebrations have been influenced over time by Christian holidays, plagues, and religious persecution.