A popular festival day and a public holiday in many nations, this day is widely celebrated across the world as a secular family holiday. It is a religious holy day for observant Christians to celebrate the birth of Christ as the son of God and for a small number of Muslims to celebrate the birth of Christ as an important prophet. Christmas Day rituals can include decorating Christmas trees, feasting, singing Christmas carols and exchanging gifts. Christmas celebrations often reflect differing cultural, local and national traditions.