With Spanish permission to travel in the Americas, Alexander von Humboldt and botanist Aimé Bonpland left Spain on the corvette Pizarro. The voyage marked the start of a five-year scientific expedition focused on mapping, natural history collecting, and measuring climate and geography across the tropics.
The expedition stopped in the Canary Islands and explored Tenerife, including an ascent on Teide. This early fieldwork combined plant observations with instrument-based measurements, setting the expedition’s method: compare places using consistent data (altitude, air conditions, and geography).
After illness on board forced a change in route, Humboldt and Bonpland landed at Cumaná on the Venezuelan coast. From here they began sustained tropical observations—astronomy, weather, coastal geography, and collecting plants and animals—building the baseline for later rainforest travel inland.
In the mountains near Caripe, Humboldt and Bonpland explored the Cueva del Guácharo, documenting its geology and the cave’s distinctive night bird (the oilbird). The visit became a well-known example of their approach: careful observation of habitats and species, connected to place-based description.
After reaching Caracas, the travelers surveyed the region and climbed the Silla de Ávila (the coastal mountain ridge above the city). These climbs helped Humboldt link altitude to changes in temperature, vegetation, and human settlement—ideas that later shaped his broader “geography of plants.”
Humboldt and Bonpland set out from the Caracas region into the Venezuelan interior, traveling across the llanos (seasonally flooded grasslands) and river systems. This leg was designed to reach the upper Orinoco and investigate reports of a natural water connection to the Amazon basin.
Traveling by canoe along the Orinoco and its tributaries, the expedition reached and traveled the Casiquiare—a natural waterway connecting the Orinoco system to the Río Negro, a major Amazon tributary. Their observations helped confirm that the Orinoco and Amazon basins are connected by this channel, a major geographic result of the journey.
Near the mouth of the Casiquiare, Humboldt and Bonpland visited San Carlos de Río Negro, close to the point where travel routes and river currents link wide regions of northern South America. This stop highlighted how river geography shaped movement, borders, and contact between communities in the rainforest frontier.
After months in forest and river travel, the expedition reached Angostura (now Ciudad Bolívar), completing a long traverse between the Orinoco and Amazon-connected waterways. The party’s measurements (positions of places, magnetic observations, and collections) were followed by serious illness, showing the physical cost of tropical fieldwork.
Humboldt and Bonpland sailed to Havana to secure and ship specimens gathered in Venezuela and the Orinoco rainforest. Cuba also became a place to study plantation economics and slavery conditions alongside natural history—broadening the expedition beyond biodiversity into social and economic observation.
Leaving Cuba, the travelers returned to the mainland at Cartagena, then moved inland up the Magdalena River toward Bogotá. This shift marks the transition from lowland rainforest and river corridors to highland Andean research, where Humboldt could compare tropical ecosystems across altitude and latitude.
In Bogotá, Humboldt worked with leading colonial botanist José Celestino Mutis and drew on local scientific records and expertise. Access to collections, illustrations, and data helped Humboldt link his field observations to a wider, evidence-based picture of American geography and biodiversity.
In the Andes near Quito, Humboldt attempted Chimborazo, reaching a very high elevation for the time and carefully noting changes in air pressure, temperature, and vegetation with height. This work strengthened his idea that plant communities form zones tied to climate and altitude, not just to continent or country.
After traveling through the Americas for years (including later stages in Mexico and a short visit to the United States), Humboldt and Bonpland crossed the Atlantic and arrived back in Europe. Their return marked a turning point from field exploration to organizing collections and publishing results that reshaped European science’s picture of tropical nature and geography.
Alexander von Humboldt's Orinoco and Amazon Journey (1799–1804)