(FILES) Aerial view of the Mucajai river at the Yanomami indigenous territory in the state of Roraima, Brazil on February 2, 2023. What’s the longest river in the world, the Nile or the Amazon? The question has fueled a heated debate for years. Now, an expedition into the South American jungle aims to settle it for good. Using boats powered by solar energy and pedal power, an international team of explorers plans to set off in April 2024 to definitively establish the source of the Amazon in the Peruvian Andes, then travel nearly 7,000 kilometers (4,350 miles) across Colombia and Brazil, to the massive river’s mouth on the Atlantic. (Photo by MICHAEL DANTAS / AFP)