Roosevelt loses the presidential election, and Republican friends blame him for splitting their party's vote by running as a third-party candidate.

Argentina's Museo Social invites Roosevelt to South America as a guest lecturer, giving him a reason to visit the continent.

Roosevelt impulsively changes the expedition's safe itinerary to an exploration of the uncharted and dangerous River of Doubt.

Edith Roosevelt asks her son Kermit to join the expedition to protect his ailing father; Kermit reluctantly agrees out of duty.

The expedition crosses the Brazilian highlands as pack animals collapse and die from the harsh conditions.

At a remote telegraph station, the group learns that Margaret Roosevelt has died of typhoid fever back in New York.

The 22-person expedition launches onto the River of Doubt in heavy, difficult-to-maneuver dugout canoes.

Simplicio drowns in the rapids after Kermit disobeys Rondon's orders and steers into dangerous white water.

Rondon takes his dog Lobo hunting and the dog is shot with poisonous arrows by an unseen Indigenous group.

De Lima shoots and kills Paishon, the respected leader of the Brazilian soldiers, after being confronted about stealing food.

Gravely ill and fearing he will slow the group, Roosevelt resolves to die by suicide rather than endanger his companions.

Kermit refuses to leave his father to die and devises a plan to lower the boats over the falls using ropes.

Rubber tappers sell the starving expedition food and canoes and guide them safely through a treacherous set of rapids.

Roosevelt's leg infection worsens so severely that Dr. Cajazeira operates on the abscess in the jungle without anesthesia.

Roosevelt sails into New York harbor looking gaunt and frail, shocking the crowds who came to celebrate his return.

After losing the presidential election, Theodore Roosevelt sought adventure in South America and impulsively agreed to explore the uncharted River of Doubt. His son Kermit joined the expedition at the request of Roosevelt's worried wife, Edith, and would prove essential to his father's survival. The group faced the brutal conditions of the Amazon—losing men, boats, and rations—while navigating treacherous rapids and evading hostile Indigenous groups. When Roosevelt's infected leg and malaria left him near death, he resolved to die by suicide rather than slow the others, but Kermit refused to accept this and devised a rope system to save the expedition. The group finally escaped starvation when they encountered rubber tappers who resupplied them and guided them to safety. Roosevelt returned to New York a shadow of his former self but had achieved the monumental feat of placing a thousand-mile river on the map.

The headline events of Roosevelt's journey from political defeat to Amazon survival.

Roosevelt is shot during a campaign speech in Milwaukee but continues delivering the speech despite the bullet lodged in his body.

Father Zahm assumes responsibility for planning the South American expedition despite lacking the qualifications or experience for the role.

Zahm enlists Anthony Fiala to order expedition provisions, and Fiala packs luxury items at the expense of necessary supplies.

Frank Chapman recruits George Cherrie, a naturalist with 25 years of South American experience, to accompany Roosevelt on the expedition.

Roosevelt boards the Vandyck and departs for South America, feeling refreshed and renewed as soon as he leaves New York.

The group arrives at Tapirapoan and chaos erupts because the Americans have brought far too much baggage for the available mules.

Zahm requests that Pareci men carry him; Roosevelt collects signatures from ten expedition members condemning Zahm and dismisses him.

Anthony Fiala is cut from the main expedition and assigned to lead a separate trip down the Papagaio River instead.

Rondon arranges the purchase of seven heavy dugout canoes from the Nhambiquara people to replace the pack animals lost on the trek.

On the expedition's first day on the river, sighting rods are planted 114 times and the group covers only six miles.

Two boats snap their moorings overnight and are swept away downstream, stranding the group with only five canoes remaining.

With only five canoes remaining and no appropriate trees at hand, the men spend four days hand-building a replacement dugout.

Rondon halts the expedition at a large tributary, claiming to search for de Lima; Roosevelt suspects the real motive is surveying.

The expedition reaches the rendezvous point with Pyrineus's soldiers; Roosevelt looks up from his weakened state to see both national flags flying.

Roosevelt gives a speech to the National Geographic Society, drawing the River of Doubt with chalk to silence doubting explorers.

The expedition was undermined from the start by poor planning and the wrong personnel, from Anthony Fiala's ill-suited provisions to Father Zahm's racist behavior that eventually got him dismissed. George Cherrie, recruited by Frank Chapman, was one of the few genuinely qualified members, and his experience proved vital throughout the journey. The early overland trek exposed the expedition's unpreparedness as pack animals died and the group had to shed almost everything before even reaching the river. Once on the water, the slow pace of surveying and repeated boat losses created mounting crises, including the need to build a new canoe by hand deep in the jungle. Tensions over Rondon's delaying tactics came to a head when he paused the starving expedition at a tributary, an act Roosevelt read as a pretext to survey rather than a genuine search for the fugitive de Lima. The expedition ultimately survived to reach its rendezvous, and Roosevelt defended its extraordinary findings before the world at the National Geographic Society.

The key supporting events that shaped and sustained the expedition.

After his election loss, Roosevelt withdraws to Sagamore Hill, shunned by the Republican allies who had once celebrated him.

Roosevelt consults the American Museum of Natural History, and director Henry Osborn pledges support and provides two experienced naturalists for the expedition.

Brazilian foreign minister Lauro Müller asks Roosevelt why he is not sailing down an unexplored river, planting the idea that transforms the expedition.

Roosevelt and Rondon board the Nyoac steamboat to begin their journey; Roosevelt demonstrates his endurance on a hunting trip while others rest exhausted.

The expedition discovers the vertically buried bodies of two Brazilian soldiers killed by the Nhambiquara, a grim warning of the dangers ahead.

The group arrives at the River of Doubt having lost all pack animals on the trek, with no boats of their own.

A member nearly steps on a deadly coral snake at camp; it lunges at Roosevelt's foot but his leather boot stops the fangs.

Three days into the journey, the river current quickens sharply and the group faces six-foot waterfalls, forcing a grueling two-and-a-half-day overland portage.

While helping save a boat from the rapids, Roosevelt slips on a boulder and cuts his leg, and the wound quickly becomes infected.

Rondon formally announces that the River of Doubt will be renamed the Roosevelt after the expedition discovers a large confirming tributary.

Roosevelt's fever reaches 103 degrees and he tells Rondon to proceed without him if he falls into a coma.

Roosevelt's fever breaks and, refusing to be carried, he walks with assistance to the next campsite rather than accept help from the soldiers.

The group passes de Lima on the riverbank as he cries out for help, and every member of the expedition refuses to stop.

A bejuca vine cut with a knife or axe—a tool Indigenous peoples did not use—signals that rubber tappers are nearby.

Roosevelt dies at home, his life shortened by the infections and recurring malaria contracted on the Amazon expedition.

The expedition's fate was shaped by a series of turning points, beginning with a casual question from a foreign minister that sent Roosevelt down a river no one had ever mapped. From the buried bodies of murdered soldiers that foreshadowed the dangers ahead, to the arrival at the river with no boats, each discovery raised the stakes further. Small moments—a snake lunging at Roosevelt's foot, a leg cut on a boulder—carried enormous consequences in an environment where any injury could mean death. The discovery of a large tributary that Rondon named after Roosevelt was a rare moment of triumph, but it was soon overshadowed by Roosevelt's near-fatal fever and his quiet instruction to abandon him if he fell into a coma. The expedition's survival ultimately depended on two final revelations: a cut vine that signaled rubber tappers were near, and the cold collective decision to pass de Lima on the shore and leave his fate to the jungle. Roosevelt never fully recovered, and the expedition cost him his remaining years of life.

The critical decisions and revelations that determined the expedition's survival or failure.