Christmas is Christian holiday that celebrates the birth of Jesus Christ. For millions of Christians throughout the world it is the happiest and the busiest time of the year. No one knows the exact date of Christ's birth but most Christians celebrate Christmas on December 25. The world Christmas comes from Christes masse, an early English phrase that means Mass of Christ. People of different countries celebrate Christmas in various ways. People in the United States and Canada decorate their homes with Christmas trees, wreaths and ornaments. City streets are filled with colored lights; the sound of bells and Christmas carols can be heard everywhere. Children write letters to Santa Claus and tell him what presents they would like to get. Many department stores hire people to wear a Santa Claus costume and listen to children's reguests. People send Christmas cards to relatives and friends. Many companies give presents to their employees. A Christmas tree is one of the main symbols of Christmas in most homes. Relatives and friends may join in trimming the tree with lights, tinsel, and colorful ornaments. Presents are placed under the tree. On Christmas Eve or Christmas morning, families open their presents. Many children believe that Santa Claus arrives on Christmas Eve in a sleigh pulled by reindeer and brings presents. Some children hang up stockings so Santa Claus can fill them with candy, fruit and other small gifts. In many parts of the United States and Canada groups of people walk from house to house and sing Christinas carols. Some people give singers money or small gifts or invite them for a warm drink. Many people attend church services on Christmas Eve or Christmas morning. They listen to readings from Bible and singing Christmas carols. A traditional Christmas dinner consists of stuffed turkey, mashed potatoes, cranberry sauce and a variety of other dishes. Some families have ham or roast goose instead of turkey. Pumpkin pie, plum pudding, and fruitcake are favourite desserts.