The Roosevelt-Rondon Expedition refers to a scientific expedition that took place in 1913-1914 in the Amazon rain forest. Led by former US President Theodore Roosevelt and Brazilian explorer Colonel Candido Rondon, the expedition aimed to explore and map the River of Doubt (later renamed Roosevelt River) in the Brazilian state of Rondonia.

The expedition was arduous and faced numerous challenges, including navigating treacherous waters, fighting off deadly animals and insects, and dealing with diseases like malaria. Several members of the expedition fell ill and died, while others suffered injuries or had to turn back.

The expedition was also significant in terms of scientific discoveries. It documented various species of plants and animals that were previously unknown to science. The team encountered indigenous tribes along the way and made efforts to establish peaceful relations and gather information about their way of life.

The Roosevelt-Rondon Expedition played a crucial role in highlighting the environmental and cultural importance of the Amazon rainforest. It helped raise public awareness about the need for conservation efforts and paved the way for further scientific exploration in the region.