In a stunning milestone for justice in Central America, a Guatemalan court recently charged former dictator Efraín Rios Montt with genocide for his brutal war against the country's Mayan people in the 1980s — and Pamela Yates' 1983 documentary, When the Mountains Tremble, provided key evidence for bringing the indictment. Granito: How to Nail a Dictator tells the extraordinary story of how a film, aiding a new generation of human rights activists, became a granito — a tiny grain of sand — that helped tip the scales of justice. An Official Selection of the 2011 Sundance Film Festival. A co-production of ITVS. A co-presentation with Latino Public Broadcasting.