I would say that it was the Sepoy Rebellion.
Answer:
497-1514 Europeans see Florida for the first time.
1513 - In 1513, Spaniard Juan Ponce de Leon became the European to explore Florida.
1539 - Hernando de Soto landed in the Tampa Bay.
1542 - De Soto died near the Mississippi River.
Explanation:
I think it's the election of Dwight D. Eisenhower. All of the other choices were done in the name of civil rights. Rosa Parks' not giving up her seat led to boycotts on public transportation. Freedom rides through the south were used as a civil demand for freedom. The march from Selma to Montgomery was an act of civil disobedience in an extremely racist country. The only choice that doesn't fit would have to be Dwight's inauguration.