to Europe to research the project, but his visits to the concentration camps so disturbed him he returned to Hollywood determined to write and direct a musical comedy instead. He had known Bing Crosby since the crooner's days with Paul Whiteman, and he and Brackett had contributed to Crosby's film Rhythm on the River (1940). Since Crosby was Paramount's leading star and Wilder was the studio's top director, it was easy to convince executives to greenlight a collaboration between the two men. Wilder recalled reading about Valdemar Poulsen, a Danish inventor who had demonstrated a magnetic recording device for Franz Joseph I of Austria in the hope the Emperor would help finance his invention, and he and Brackett used this bit of historical fact as the starting point for their screenplay, which initially was titled Viennese Story. Principal photography began in Jasper National Park in the Canadian Rockies in the province of Alberta in June 1946. It cost the studio $20,000 to have pines shipped from California and planted on location because Wilder was unhappy with the look of the native trees. He also planted 4,000 white daisies dyed blue so they would photograph better. Working with Bing Crosby proved to be problematic from the start. Between scenes he barely interacted with leading lady Joan Fontaine, on loan from RKO Radio Pictures, who later recalled: "Crosby wasn't very courteous to me ... There was never the usual costar rapport. I was a star at that time, but he treated me like he'd never heard of me." The singer tended to ignore his director as well. According to Fontaine: "It wasn't that he had anything against Mr. Wilder. He just didn't pay much attention to him. He told me once that he had some trouble understanding his funny accent." Worst of all, Crosby tended to alter his dialogue, saying it "as he felt it at the moment", and Wilder was known for insisting his lines be delivered exactly as written. "Bing Crosby operated for himself, not for the group or the film", Wilder recalled. "He was a big star, the biggest, and he thought he knew what was good for him. He sensed what his audience expected and he knew how to deliver that. The picture didn’t come out what I wanted, but that wasn’t Crosby’s fault. It was mine.” Another book has an opposing view stating "Contradicting other accounts, Wilder