There's more than meets the eye in Christopher Nolan's Inception (as if that weren't enough). Now, a short YouTube video has gone viral prodding moviegoers who return to the theater to pay attention with their ears as well. The video reveals that Hans Zimmer, who created the soundtrack for the movie, employed a slowed-down version of several notes from the recording of Edith Piaf's "Non, je ne Regrette Rien" throughout the film. The actual recording is played at normal speed to awaken the characters at key moments in the film. (One of the characters is played by Marion Cotillard, who portrayed Piaf memorably in La Vie en Rose .) Contacted by the New York Times , Zimmer said that he had seen the video. "I was surprised how long it took them to figure it out," he said. The musical "cue," as it is called, was meant to be a "signpost," Zimmer said as the characters entered different levels of dreaming or reality. In fact, all of the music in the film amounts to "subdivisions and multiplications of the tempo of the Edith Piaf track" that would signal "a different level of time." Zimmer added "Everybody thinks the dream is the important part. ... For me, the time was the important part the idea that, in a peculiar way, Chris had made a time-travel movie that actually worked."