The Rio da Duvida (or 'River of Doubt') in Brazil, re-named The Roosevelt River (Rio Roosevelt, sometimes Rio Teodoro) after exploration by President of the United States Theodore Roosevelt who 'probed the secrets of the Amazon' all along the 930-mile river which now bears his name during the Roosevelt-Rondon Scientific Expedition of 1913?14. Roosevelt later wrote Through the Brazilian Wilderness recounting his adventures.