How did Vasco Nunez de Balboa and Ferdinand Magellan contribute to crossing the Pacific Ocean?

Vasco Nunez de Balboa and Ferdinand Magellan both played an important role in the first European crossing of the Pacific Ocean. Balboa was a Spanish explorer and conquistador. In 1513, he crossed the Isthmus of Panama, becoming the first European to cross the American continent. In so doing, he became the first European to see the Pacific Ocean, which he named the "South Sea."

Ferdinand Magellan was a Portuguese explorer who organized and embarked on a Spanish expedition into the South Sea. He and his men sailed around the southern tip of South America--through the Strait of Magellan--to reach the Pacific Ocean. He thus became the first European to cross from the Atlantic into the Pacific.

Magellan continued sailing westward, and after a harrowing journey he reached Asia (he named the ocean "Pacific" because much of it was very calm). Magellan later died in a skirmish with natives, but some of his men continued sailing west and eventually reached Spain in 1522. Thus, Magellan's expedition was the first to successfully circumnavigate the world.