In October 2019, a large multidisciplinary team of geologists, biologists, social scientists, and local residents explored the rivers, forests, and human communities around the junction of the Putumayo and Cotuhe Rivers in the lowland Amazonian regions of Colombia and Peru. This report describes what is known to date about the region’s geology, hydrology, and plant, fish, amphibian, reptile, bird, and mammal communities, as well as the present-day and historical use of its rich natural resources by communities. At the heart of the report is a series of recommendations for protecting this extraordinary landscape and the region’s natural resources in partnership with local indigenous and campesino residents. The text is in Spanish and English.