Lucia happens at the time of year when the days are shortest. The sun barely comes up in the north of Sweden. The Lucia procession is a way of bringing light into the dark - lots of small candles together turn a dark room bright and warm.
Every school in Sweden picks one student each year to be Lucia. She wears the famous crown of candles (often electric ones for safety) and leads the procession. Behind her come other children, also in white, each carrying their own candle. Some carry stars on sticks, some wear gingerbread-shaped hats.
The procession sings a special set of slow, gentle songs. The most famous is 'Sankta Lucia', a beautiful tune that almost every Swedish child knows by heart. They sing in care homes, schools, hospitals and town squares - bringing music to people who might be alone in the dark winter.
After the singing comes the food. Lucia is famous for two treats: saffron buns called 'lussekatter' (curled into a S-shape with raisins on the corners and bright yellow from saffron), and gingerbread biscuits called 'pepparkakor'. Every Swedish kitchen smells of saffron and ginger on the morning of 13 December.