A visual highlight of the Roald Dahl Plass along Cardiff Bay is a 70 foot, stainless steel rectangle by William Pye called the Water Tower. I liked the way the water fountain reflected the retail stores in Mermaid Quay. But the audience of BBC’s TV series “Torchwood” recognizes it as the entrance to The Hub headquarters. Fans also enjoy the Doctor Who Experience attraction within walking distance. Really avid fans take bus tours of local filming locations. The Roath Lock studios are also located in Cardiff.