Where does Halloween actually come from?

Halloween is an annual festival on 31. October is celebrated in many countries of the world. There are several theories as to where Halloween came from, but the most commonly accepted explanation is that it is a combination of the Celtic festival of Samhain and the Christian feast of All Saints.
Halloween is about dressing up and handing out candy to kids who come to the doors. However, in recent years, Halloween has become a popular holiday for adults, with many people going to Halloween parties or meeting with friends.