It's a tradition in many countries to decorate a tree with lights and ornaments during the holiday season. The tradition started in Germany and has since spread to many other countries, including the United States. The tree represents the evergreen tree used to decorate homes in pre-Christian times and symbolizes everlasting life and joy. The lights represent the stars in the sky and the ornaments are often symbols of hope, peace, and love. Many people also put presents under the tree for family and friends to open on Christmas morning.