What did Hernando de SoTo find on his explorer?

Hernando de Soto discovered the Mississippi River.

Explanation:

In 1539 Hernando de Soto and five hundred adventurers began on a journey of exploration that would take 4 years and would travel through 10 states in the southeast United States. His goal was to discover a source of wealth, preferably gold, and around his mines establish a settlement.                                                                                                             Hernando de Soto and his expedition became the first Europeans to see   and cross the mighty Mississippi River.