As pumpkins pile high on supermarket shelves and costumes emerge from storage, Halloween approaches, ready to cast its yearly spell on October 31. Known in full as All Hallows’ Evening, or Halloween, this festivity intertwines ancient Celtic roots with Christian traditions and a growing culture of costumes, trick-or-treating, and more. Here’s how Halloween evolved into the cultural phenomenon it is today—and where you can find the best celebrations across Britain.

Halloween’s Ancient Beginnings Halloween’s origins trace back to the Celtic regions of Britain and Ireland, with the ancient festival of Samhain, meaning “Summer’s End.” This pagan event marked the end of the harvest and was thought to be a night when the veil between the worlds of the living and the dead became thin, allowing spirits to roam. Gaels, native to areas including Ireland and Scotland, would leave out food and drink as offerings to keep wandering spirits at bay and held elaborate bonfires to drive away malevolent forces.

By the 9th century, Christian influence brought All Saints’ Day on November 1, turning the night before into a celebration known as All Hallows’ Eve, or Halloween. This merging of Christian and Celtic traditions gradually transformed Halloween into the vibrant holiday celebrated today. From “Souling” to Sweets The custom of going door-to-door traces back to the 16th century in Britain and Ireland.

People would dress in costumes and offer songs, prayers, or poems i.