At the request of the provincial council of Limburg, Sien produced a sound and light show for the open-air museum of Bokrijk. It had to be an all-weather attraction that would bring in visitors during the quiet winter season. Anne Rutyne wrote a new Flemish legend based on the myths of the Will-o’-the-wisp, water spirits and gnomes. This legend was brilliantly interpreted and recorded by the great master Herbert Flack and emphasised by magical special effects. The final result was a fully automated sound and light show. This production ran every winter for six years.