Caillou is a Canadian educational children's television series that was first shown on Télétoon and Teletoon, with its first episode airing on the former channel on September 15, 1997; the show later moved to Treehouse TV, with its final episode being shown on that channel on October 3, 2010. The series is based on the books by Hélène Desputeaux. It centers on a 4-year-old boy named Caillou who is fascinated by the world around him.