Last year, according to the National Retail Federation, Americans spent about $7 billion on candy, costumes, decorations, and more for Halloween. That statistic was up 18 percent from 2014 retail numbers that sat more in the $5.8 billion range, which means that in 2015 Halloween had more growth than all winter holidays­—Thanksgiving, Christmas, Kwanzaa, Hanukah, etc.—combined which only experienced a 3 percent spike in growth. While Halloween isn’t actually the second most popular holiday in the United States, as many believe it is, it is the fastest growing.

With this growth, most of which is due to increased numbers of adults and aging teens celebrating Halloween, curiosity over the holiday has also grown. Dressing up and going door to door for free candy is all good fun, but what are we really recognizing when celebrating Halloween?

2,000 years ago, the Celts celebrated a post-autumn pre-winter holiday known as Samhain (pronounced sow-in) on October 31^st and November 1^st, the eve and day of the Celtic New Year. Samhain was, and is, a celebration of harvest and recognition of the spirits of those who have passed during which the Celts would have bonfires, wear costumes, and make offerings of food to spirits. The Celts believed that on Samhain the veil between worlds was at its thinnest and spirits would return to Earth and could commune with the living. Being a culture that relied heavily on the natural world, the Celts considered this an important time to communicate with spirits about predictions for the coming winter.

In mid-40 A.D., the majority of Celtic territories had been conquered by the Roman Empire, and the Romans took the traditions the Celts had upheld during Samhain and integrated them into their own end-of-October celebrations. These celebrations, which recognized the passing of their dead—a day formerly known as Feralia—and the Goddess of fruit and trees, Pomona, are attributed to having introduced the association of Halloween with apples since apples were the symbol of Pomona.

Sometime after the collapse of the Western Roman Empire—around the early 600s—Christianity began to come into the picture surrounding Celtic and Roman holidays as Pope Gregory III moved what was previously known as All Martyrs Day from May 13^th to November 1^st , and turned it into All Saints Day. That was followed by the creation of All Souls’ Day on November 2^nd in the year 1000 A.D., created as a day to recognize the dead, and the evening before the two holidays, October 31^st, began to be known as All-Hollows Eve.

Halloween traditions in America can be dated to the mid-19^th century when Irish immigrants brought the customs over to the United States while fleeing famine in Ireland. By the 20^th century, Halloween had been dictated a children’s holiday, but it has grown to be more widely accepted and celebrated by institutions and older Americans as its presence in our culture has continued.

Nowadays, we celebrate Halloween as a community event, a time to have autumn block parties, bob for apples, and dress-up to go trick-or-treating. Many of the spiritual and seasonal reasons for celebrating Halloween have been lost as it has become a highly marketed and commercial holiday. Let us not forget this Halloween—as the feel of autumn leaves and we look onwards to the coming of winter—of what we are really celebrating when we dress-up and partake in eating a great deal of sweets.

This is a time of year to remember those who have passed on to another world, be thankful for the bounty of harvest and people we have around us, and look ahead to the coming dormancy of winter, with the knowledge that the green will return to the trees and the warmth to the air, come spring.