Halloween is celebrated to mark the roots of a festival that blends ancient, religious, and modern traditions. Its origins lie in the Celtic festival of Samhain, when people believed the boundary between the living and the dead was thin and that spirits could roam freely on the night of October 31. Over time, Christian influences added All Saints’ Day (November 1), and the evening before—All Hallows’ Eve—became Halloween. Today, the holiday is largely associated with fun activities such as dressing up in costumes, carving pumpkins, trick-or-treating, and spooky decorations, with many people enjoying the festive, communal atmosphere that has developed around it.