According to the 'old' Julian calendar the day of St. Gregory was the first day of spring. And it has been known for centuries that St. Gregory announced the beginning of spring by ''threwing his lamp into the water''. The tradition of creating amazing floating art creations has been present in Vrhnika for a long time. At dusk, the Bela Spreak is illuminated with candles affixed to the colourful and inventive creations of local children. It is a magical event where children can see illuminated and floating creations, meanwhile adults can enjoy the miraculous spectacle and the joy of the youngest. Nearby, in the vicinity of the a pleasant gathering with local food and music takes place.