Beginning with Life on Earth in 1979, Attenborough set about creating a body of work which became a benchmark of quality in wildlife film-making and influenced a generation of documentary film-makers. The series also established many of the hallmarks of the BBC's natural history output. By treating his subject seriously and researching the latest discoveries, Attenborough and his production team gained the trust of scientists, who responded by allowing him to feature their subjects in his programmes. In Rwanda, for example, Attenborough and his crew were granted privileged access to film Dian Fossey's research group of mountain gorillas. Innovation was another factor in Life on Earth's success: new film-making techniques were devised to get the shots Attenborough wanted, with a focus on events and animals that were hitherto unfilmed. Computerised airline schedules, which had only recently been introduced, enabled the series to be elaborately devised so that Attenborough visited several locations around the globe in each episode, sometimes even changing continents mid-sentence. Although appearing as the on-screen presenter, he consciously restricted his time on camera to give his subjects top billing.