Exploration
In the Pacific Ocean, Jorge de Menezes (c. 1498–?), discovered Papua New Guinea. García Jofre de Loaísa (1490–1526), discovered the Marshall Islands. Explorations of the Americas began with the initial discovery of America by Christopher Columbus (1451–1506), who led a Castilian (Spanish) expedition across the Atlantic, discovering America. After the discovery of America by Columbus, a number of important expeditions were sent out to explore the Western Hemisphere. This included Juan Ponce de León (1474–1521), who discovered and mapped the coast of Florida; Vasco Núñez de Balboa (c. 1475–1519), who was the first European to view the Pacific Ocean from American shores (after crossing the Isthmus of Panama) confirming that America was a separate continent from Asia; Aleixo Garcia (14?–1527), who explored the territories of present-day southern Brazil, Paraguay and Bolivia, crossing the Chaco and reaching the Andes (near Sucre).
Alexander von Humboldt
Leaving from Cuba, Humboldt decided to take an unplanned short visit to the United States. Knowing that the current U.S. president, Thomas Jefferson, was himself a scientist, Humboldt wrote to him saying that he would be in the United States. Jefferson warmly replied, inviting him to visit the White House in the nation's new capital. In his letter Humboldt had gained Jefferson's interest by mentioning that he had discovered mammoth teeth near the Equator. Jefferson had previously written that he believed mammoths had never lived so far south. Humboldt had also hinted at his knowledge of New Spain.