How did Halloween begin? The holiday traces back to the ancient Celtic festival known as Samhain. The ancient Celts from Britain and Ireland observed the start of the new year on November 1, All Souls Day. The day marked the end of summer and the harvest. Folks came to believe that on October 31, the worlds of the living and dead overlapped before the start of the new year. October 31 became All Hallows Eve, a time where the ghosts of the dead could return to destroy the harvest that was stored for winter. People set bonfires on hilltops to ward off the evil spirits before the start of the winter season. Look through this slideshow to learn how more Halloween traditions began.

The origin of trick-or-treating may have also come from Celtic tradition. Poor children in Britain and Ireland went door-to-door on All Hallows Eve and received food in exchange for the promise of praying for the giver’s dead relatives on All Saints Day. This practice was known as “going-a-souling.” While that may be the start of it, that tradition didn’t make its way to America. Here, trick-or-treating may have started with children trading songs for treats in the 1910s, according to old newspaper texts. The tradition didn’t really take off until after World War II, when popular children’s magazines started discussing it and the idea entered popular culture, including radio shows and cartoons.

There are many legends surrounding the Jack’-o’-Lantern and where he got his name. However, the tradition began with folks believing that carving scary faces onto turnips would frighten away evil spirits. The tradition turned to pumpkins in America because pumpkins were more plentiful—and much easier to carve.

During the Samhain festival, some people wore masks and other disguises to avoid being recognized by evil spirits. But the rise of costumes as a major part of Halloween actually took off in the United States as Halloween became a consumer holiday. Initial reports of mass-produced costumes date to as early as the 1930s. They really took off with the rise of trick-or-treating.

The ideas of death and fearing spirits that surrounded All Hallows Eve gave rise to the skeleton and ghost imagery. As for the fascination with witches, it appears that the European interest in witches was brought to America. It joined with the Native American beliefs in evil spirits, which both fit with the spooky themes of October 31. That association gave witches and black cats—the Celtic priests had convinced people that black cats were humans gone bad—a rise in popular culture as symbols of Halloween.

The idea of having Haunted Houses was created simply as a way to make money. Playing off the obvious themes of Halloween, the first haunted houses were fundraising efforts led by the Junior Chamber International (Jaycees) clubs and have continued as fundraising and commercial operations. Boo!