Soon after Columbus made his voyage to America, Spaniards kept the discovered land in strict isolation from the remaining part of the world. Other nations were not admitted, and spreading information on geography, the nature and native people was banned until the early 19th century. It was as late as in the 18th century when the French managed to organise two expeditions, but comprehensive scientific studies on the area covering current Venezuela, Ecuador and Peru were made by Alexander Humboldt, an eminent German scientist. The article presents the results and significance of his expedition.