The annual candlelit Lucia procession on  December 13 is one of the more exotic Swedish customs, with girls and boys clad in white full-length gowns singing songs together. When the 400-year-old tradition of St. Lucia is celebrated, you will see thousands of young girls emerge from the darkness of a Swedish winter’s day and gently silence the crowds with a procession of light. How exactly is Lucia Day celebrated in Sweden? Johan Alvin, the Swedish Embassy's second secretary and his wife Marika Alvin will give you the answer. Picture: The Lucia choir in Hanoi.