Who discovered the Mississippi river San Salvador and the pacific ocean?

The Mississippi River was explored by French explorer Jacques Marquette and Louis Jolliet in 1673. San Salvador, the first island encountered by Christopher Columbus in 1492, is associated with his discovery of the Americas. The Pacific Ocean was first reached by Vasco Núñez de Balboa in 1513 when he crossed the Isthmus of Panama and became the first European to see the ocean from the New World.