Dian Fossey changed the way people view gorillas. She told the world how they lived and dedicated years to fighting a battle against encroaching gorilla poachers. Her obsession may have ended up killing her. Three decades after Fossey was murdered in a remote mountain cabin in Rwanda, National Geographic looks back at her life and legacy, from childhood and her early days researching in Congo, through to her arrival in Rwanda, where she spent 18 years studying and protecting the mountain gorilla population. Featured across three parts are extensive use of archival footage and still images, interviews with people who knew and worked with Dian -- including Wayne McGuire, the man convicted in absentia of her murder -- and the primatologist's own writings. The series is narrated by Sigourney Weaver, who won a Golden Globe for her portrayal of Fossey in the 1988 film "Gorillas in the Mist."