Article continues below advertisementIt's been 20 years since Jack Twist and Ennis Del Mar first forged a bond while herding sheep on Brokeback Mountain. The film, directed by Ang Lee and based on Annie Proulx's 1997 short story, forever changed the course of queer American cinema.Article continues below advertisementSource: @FocusFeatures/YOUTUBE'Brokeback Mountain' marks its 20th anniversary this year.Article continues below advertisementLee firmly believes Brokeback Mountain is "uniquely, and universally, a great American love story.