 Prior to Crown Fountain , Plensa 's dominant theme had been dualism , which he had expanded to artworks in which the viewers are outside , and the visible subjects of the art are inside containers and hollow spaces . In the 1990s , he completed several outdoor sculptures in which he explored the use of light ( The Star of David ( 1998 ) at Stockholm 's Raoul <unk> Square , Bridge of Light ( 1998 ) in Jerusalem ) , and LED technology , video , and computer design ( <unk> <unk> & Mr. Net in <unk> ( 1999 – 2000 ) ) . In his public art , Plensa challenged himself to involve the viewer with his art , which led to his conception of the Crown Fountain . His objective was to create a socially relevant , interactive fountain for the 21st century . Since water is the focus of a fountain , and since Chicago , and especially Millennium Park , is so greatly affected by the nearby waterfront , Plensa sought to create an eternal water work to complement the local natural inspirations . Because of the colder winters common to the climate of Chicago , Plensa created a fountain that would remain vibrant when the water was inactive in the <unk> , so the fountain is an experience of light themes and the use of video technology . 
