We describe the evolution of a innovative proposal that RNP, the Brazilian NREN, presented in 2013 to lay optical communication cables along the courses of the large rivers found in the Amazon basin of South America, where the population is concentrated along the rivers, that provide food and transport for the inhabitants. The original motivation was to replace satellite communication by terrestrial broadband communication for the not insignificant number of RNP client organisations in higher education and research in this very large region of Brazil (almost half the size of Europe). This proposal has been well received in Brazil, especially by different government ministries and agencies active in the Amazon basin, and the Brazilian Army has plans to install such a connection along the River Solimões (Upper Amazon) from the regional capital of Manaus to the border with Peru and Colombia by the end of 2016, and to cable all major rivers in the region by 2018. The main benefits for the population will be to provide access to broadband communications, and thus to telehealth, improved education and other government-provided services, as well as greater economic and social integration within the country. For the research and higher education communities, this improved connectivity will enable more sophisticated data collection, advancing our knowledge and understanding of tropical environments, as well as greater collaboration with their colleagues both within and outside the region,. Similar projects are or have been considered in Peru and Colombia, and there are good prospects for integrating telecommunications networks in the three countries in order to provide coast to coast connectivity between the Atlantic and Pacific Oceans.