For decades, American high school teacher Bruce Farrer has been asking his students to write letters to their future selves. 20 years later, he tracks down the students and posts their letters to them. Speaking in a video for US airline West Jet, Farrer says that the letters have become more valuable because we now communicate far less by letters than we did 20 years ago. He created the assignment because he wanted his students to do an exercise "that was different, that would be interesting and one that they would value". An old pupil of Farrer says when he was asked to write a 10 page letter to his future self, he thought it was "a lesson just to pass the time, to keep us busy for a few hours while he did other things". He now understands what a dedicated teacher Farrer was. Of course, tracking down your students 20 years after teaching them is a challenging task. Farrer describes it as "a lot of detective work" but he is excited to find out the different paths his ex-pupils have taken. The video shows the reactions of some of Farrer's old students upon opening their letters. One describes it as an "emotional roller-coaster" as she reads about the passing of her grandmother and aunt, experienced through the eyes of her younger self. Despite the profound effect that receiving the letters has on its recipients, Farrer remains modest about his diligence and commitment. "I'm just a regular teacher who happened to assign a rather different assignment", he says.