In Madrid, Alexander von Humboldt secured authorization from the Spanish Crown to travel and do scientific research in Spain’s American territories. This official permission was essential because foreign research travel in the Spanish Empire was tightly controlled. It set the expedition’s legal and political foundation before any fieldwork began.
Humboldt and the French botanist Aimé Bonpland left Spain for the Americas on the corvette Pizarro. They carried instruments for measuring latitude/longitude, Earth’s magnetism, and climate, reflecting their goal of making careful, repeatable observations. The voyage marked the start of five years of travel and data collection in Spanish America.
The expedition stopped in the Canary Islands, where Humboldt climbed the volcano Teide. This early climb helped him practice high-altitude measurement and observation—skills he would use later in the Andes. It also shows how the journey mixed travel logistics with scientific work from the very beginning.
Humboldt and Bonpland landed at Cumaná (in today’s Venezuela), starting their on-the-ground research in Spanish America. From this base they began observing climate, plants, animals, and local geography. The landing also began a long phase of travel through northern South America by foot, horse, and river canoe.
Near Caripe, Humboldt and Bonpland explored the Cueva del Guácharo, a major cave system known for large populations of oilbirds (guácharos). Humboldt recognized the birds as a distinct species and recorded detailed natural history observations. The episode became one of the expedition’s best-known early studies of tropical ecosystems.
Humboldt and Bonpland began an extended river journey aimed at understanding the Orinoco basin and its connections to other South American river systems. Traveling by canoe, they combined mapping, astronomical positioning, and biological collecting. This phase pushed the expedition into remote areas and tested their ability to do science under difficult conditions.
In the Casiquiare region, Humboldt and Bonpland gathered observations supporting that this natural waterway links the Orinoco and Amazon basins. Demonstrating this connection mattered for European geographic knowledge because it clarified how two of the world’s largest river systems relate. The work also reflected Humboldt’s emphasis on measurement-based geography rather than relying on secondhand reports.
After returning from the interior, Humboldt and Bonpland sailed to Cuba and arrived in Havana. Humboldt used the stay to study colonial society and economy, and to make scientific measurements (including geographic positioning and harbor observations). Cuba also served as a practical stop for organizing and protecting specimens collected in Venezuela.
The expedition reached Bogotá and met the prominent Spanish botanist José Celestino Mutis. Access to Mutis’s botanical network and records helped Humboldt connect his field collections to broader scientific work already underway in the Spanish Empire. This period strengthened the expedition’s scientific credibility and expanded its comparative approach to plants and environments.
Humboldt and Bonpland reached Quito, shifting the expedition toward high-mountain research in the northern Andes. From Quito they carried out climbs and measurements that linked altitude with temperature, pressure, and plant distribution. This Andean phase became central to Humboldt’s later ideas about how nature changes across elevation and climate zones.
Humboldt, Bonpland, and their party attempted Chimborazo, then widely considered among the highest mountains in the world. They turned back short of the summit due to dangerous crevasses and the physical effects of altitude, but reached a record height for the time. Humboldt’s careful notes on conditions and vegetation helped shape his emerging “plant geography,” linking living things to environment.
The expedition reached Lima after crossing the Andes toward the Pacific coast. Along the Peruvian coast, Humboldt made systematic ocean and climate observations that helped explain why some tropical coasts are cooler and drier than expected. This work connected ocean conditions to regional climate, a key part of Humboldt’s “nature as an interlinked system” approach.
After traveling by sea along the Pacific coast, Humboldt sailed from Guayaquil toward Mexico and continued measuring ocean conditions. The journey brought the expedition into New Spain (Mexico), where Humboldt would gather extensive information on mining, geography, and administration. This transition mattered because it broadened the expedition from natural history into economic and political geography.
Humboldt arrived at Acapulco and began astronomical observations to improve geographic accuracy. Over the following months, he traveled through New Spain gathering data on mines, landscapes, and population, building a detailed picture of the colony. This Mexican phase strongly influenced his later published analysis of New Spain and became widely used by scholars and policymakers.
While preparing to travel north, Humboldt wrote to U.S. President Thomas Jefferson, signaling that he could share information about Spanish America and the borderlands. The letter shows Humboldt acting not only as a naturalist but also as a major source of geographic and political knowledge. It also set up his later meetings with American leaders and scientists.
After time in the United States, Humboldt and Bonpland left Philadelphia with their collections and notes, beginning the trip back across the Atlantic. The departure marked the end of their field expedition and the start of a long period of organizing, analyzing, and publishing results. Their return also ensured that specimens, measurements, and maps could circulate widely in European scientific networks.
The expedition’s return reached the Garonne River near Bordeaux, bringing five years of travel to a close. With fieldwork finished, Humboldt could focus on turning observations into publications, atlases, and comparative scientific arguments. This endpoint matters because the expedition’s lasting impact came through the analysis and publication that followed, not only the journey itself.
Alexander von Humboldt's Exploration of Spanish America (1799–1804)