Who found out that the pacific lay on the other side of America?

The realization that the Pacific Ocean lay on the other side of America was largely attributed to explorers like Ferdinand Magellan, who, in the early 16th century, navigated around South America and became the first European to reach the Pacific from the Atlantic. However, it was later expeditions, such as those by explorers like Vasco Núñez de Balboa, who crossed the Isthmus of Panama in 1513 and saw the Pacific Ocean firsthand, that confirmed its existence. These discoveries helped to reshape European understanding of the geography of the Americas.