In 1955, the SPVEA launched the Primeiro Plano Quinquenal in response to growing international interest in Amazonia's resources and internal pressure to address the region's chronic underdevelopment. The Plano was the largest modernization plan attempted in Amazonia until then. It aimed at transforming the region's rich ecosystem into the driving force of Brazil's development as well as a major raw material provider for global markets. The article examines this neglected episode of Brazilian developmentalism as an important experience preparing the entrance of Brazil in the so-called Great Acceleration. The Plano established a rational method and constructed a technoscientific infrastructure that did not just organize the modernization of the region as a whole but formed an Anthropocene culture in Amazonia. Via their planned approach to the modernization of Amazonia, the SPVEA planners introduced new representations, demands, and expectations of the region which encouraged the exploitation of its biological reality and linked it to the advancement of Brazil. Thus, the article explores, some specificities of the Great Acceleration in the Global South and sheds new light on the political and cultural origins of the Anthropocene in Brazil.