International: Joe Biden on Sunday will be the first sitting US president to visit the Amazon -- the vast tropical rainforest that nearly killed a predecessor, Teddy Roosevelt, after he left office. The trip is part of Biden's final swing through South America before he hands the keys of the White House to Donald Trump, who becomes the United States' 47th president in two months.

Biden, 81, will touch down in the biggest city in the Amazon, Manaus, on his way to Rio de Janeiro, where a two-day G20 summit is to be held.

The Amazon jungle was not a fortunate destination for the 26th US president, Roosevelt. He had a near-death experience in it when he went on a canoe expedition there in 1914, four years after his 1901-1909 stint in office.

Roosevelt, a Republican known for his adventurous spirit, had teamed up with a Brazilian explorer, Candido Rondon, to chart the Rio da Duvida (the River of Doubt), a tributary in the wild center-west of Brazil, in the Amazon.

The river, 760 kilometers (470 miles) long, proved a formidable foe. Several members of Roosevelt's expedition died and the ex-president, aged 55 at the time, caught malaria and a leg infection, which incapacitated him in the final arduous stretch.

"T. R. (Teddy Roosevelt) was out of his mind toward the end; Rondon gave him up for dead several times," his great-grandson Tweed Roosevelt said in remarks noted by The New York Times in 1992.

Roosevelt himself, when he was warned of the dangers by friends at the American Museum of Natural History before embarking on his trip, told them he had already lived a full life and was ready for the risk. "I have had my full share, and if it is necessary for me to leave my bones in South America, I am quite ready to do so," he said, according to the Smithsonian Magazine.

In the end, the Roosevelt-Rondon expedition was saved from disaster when they came across Brazilian rubber-tappers in the jungle, who helped them enough so they could make it to cargo boats, and from there back to the safety of the outside world.

Roosevelt never fully recovered his health from his ordeal, though he and Rondon received acclaim for mapping the River of Doubt. The former president died in 1919 at home of a blood clot in his lungs, aged 60. In his honor, the river he navigated was renamed the Roosevelt River.