Marcos Santilli became a professional photographer in the early 1970s, while still studying architecture at the University of Brasilia. At the invitation of Luis Humberto Pereira, he began working at Jornal de Brasília.

After a season in London, where he went to study photography, Santilli began to work for the publisher Abril, whose branch and Brasilia covered the entire northern region. In this period, from 1974 to 79, he was able to make about 15 trips to indigenous areas. He published mainly in the magazine Veja, but also in other publications of the publisher, like the extinct Reality. He was among the Tucano and Maku, on the border of Colombia, the Urubu of Maranhão and the Xavante and Pareci, in Mato Grosso.

He also participated in an expedition to Rondônia, when he first visited the Suruí Paiter in 1978. With them, Santilli acquired great familiarity and continued to visit them over the years. The article published after the expedition, which lasted about a month, lifted the complexity of road construction and formation of cities from that road to the Amazon: hordes of immigrants implementing the civilization project in western Brazil.

The impact of these migrations on indigenous communities aroused his curiosity about the human and environmental transformations of this colonization movement in Rondônia, which led him to develop, in 1977, the Nharamaã project of audio-photographic documentation. It did not start, used its own resources to finance it, and then obtained a grant from the Guggenheim Foundation to continue this project.