CHRISTOPHER COLUMBUS

On October 12, 1492 he is credited as being the first explorer to discover America.

VASCO NUNEZ DE BALBOA

In 1510 this Spanish colonist explored the Caribbean coast of what is now Panama.  He became the first European to see the Pacific Ocean.

FERDINAND MAGELLAN

In September 1519, this Portuguese explorer set out to find an Atlantic-Pacific passage.  Near the southern tip of present-day Argentina Magellan found a narrow passage.  This passage is named for him.  It is called "The Strait of Magellan". 

STRAIT

A strait is a narrow passageway that connects two large bodies of water.

CIRCUMNAVIGATE

Means to travel around the entire earth.  Magellan's crew did that without him finally in September of 1522.