Halloween began with the ancient Celtic festival of Samhain, during which people would light bonfires and wear costumes to ward off ghosts.

During the early 20th century, people were most concerned about making their Halloween costumes as scary as possible. But it's 2021, and you'll find people taking costume inspiration from their favourite shows and celebrity figures.

Still, a tradition that remains unchanging is the children going around neighbourhoods, knocking on strangers' doors to ask for tricks and treats. The special tradition can be traced to the ancient Celts, early Roman Catholics and 17th-century British politics.

In the eighth century, Pope Gregory III set aside November 1 to honour all saints. Soon, All Saints Day incorporated some of the traditions of Samhain. The evening before was known as All Hallows Eve, and later Halloween. As time passed, Halloween became chock full of activities like trick-or-treating, carving jack-o-lanterns, festive gatherings, donning costumes and eating treats.

By the ninth century, Christianity had spread into Celtic lands, where it gradually blended with and supplanted older pagan rites. For example, in 1000 A.D., the church designated November 2 as All Souls' Day, a time for honouring the dead.

During the festivities, the impoverished would visit the houses of wealthier families and collect pastries called soul cakes in exchange for a promise to pray for the souls of the homeowners' dead relatives. The practice, also known as "souling," was then later taken up by children. Thus, the longtime practice we've all come to love.