万圣节是西方传统节日之一，通常于每年的10月31日庆祝。它的起源可以追溯到古代凯尔特人庆祝的萨温节(Samhain)。在这个节日里，人们相信死亡和生命之间的界限变得模糊，鬼魂和恶灵可以自由地穿越到人间，给人们带来危险和不幸。

为了驱赶这些恶灵，凯尔特人会点燃篝火，穿上面具和华丽的服装，以骗过恶灵。他们还会放置食物和饮料，以供已故亲人的灵魂享用。

在公元8世纪，基督教传入凯尔特地区，教会试图将这个古老的节日与基督教联系起来。因此，11月1日被定为所有圣徒节，即“万圣节”。在这个节日里，人们会去教堂祈祷，纪念已故的基督徒，以及那些被教会认为是圣徒的人。

在中世纪，万圣节逐渐演变成了庆祝鬼怪和巫术的节日。人们会穿上恐怖的服装，进行各种游戏和庆祝活动。这种庆祝方式直到今天仍在西方国家普遍存在。

总的来说，万圣节的起源可以追溯到古代凯尔特人的传统节日，后来被基督教吸收并演变成庆祝圣徒和鬼怪的节日。它已经成为西方文化中不可或缺的一部分。

Halloween, one of the traditional festivals in the West, is usually celebrated on October 31st. Its origin can be traced back to the Samhain festival celebrated by the ancient Celts. In this festival, people believed that the boundary between death and life became blurred, and ghosts and evil spirits could freely cross into the human world, bringing danger and misfortune.

To drive away these evil spirits, the Celts would light bonfires, wear masks and fancy costumes to deceive the spirits. They also placed food and drinks for the souls of their deceased loved ones to enjoy.

In the 8th century AD, Christianity spread to Celtic regions, and the Church tried to link this ancient festival to Christianity. Thus, November 1st was designated as All Saints' Day, or 'Halloween'. On this festival, people would go to church to pray, commemorate deceased Christians, and those who the Church considered to be saints.

In the Middle Ages, Halloween gradually evolved into a festival celebrating ghosts and witchcraft. People would dress up in scary costumes and engage in various games and celebrations. This way of celebrating is still prevalent in western countries today.

In summary, the origin of Halloween can be traced back to the traditional festival of the ancient Celts, which was later absorbed by Christianity and evolved into a festival celebrating saints and ghosts. It has become an integral part of Western culture.