Desc: Hidden in the Hills: Directed by Mark Kiyak. With Donna The Buffalo, The Horse Flies, Jimkata, Tara Nevins. Hidden in the Hills is a musical and cultural documentary celebrating the twentieth anniversary of the Great Blue Heron Music Festival, an annual event held in Sherman, NY. The festival draws several thousand visitors throughout the course of three days, presenting over 100 performers and conducting all kinds of workshops all within a family-friendly atmosphere. Artists who have performed there include; 10,000 Maniacs, Southern Culture on the Skids, the Horse Flies and Rusted Root.