Spanish explorers have played a significant role in the history of the Americas. Vasco Núñez de BALBOA was a Spanish explorer who is credited with being the first European to have seen or reached the Pacific Ocean in 1513. Hernando de Soto was another Spanish explorer who explored much of what is now the southeastern United States between 1539 and 1543. Juan de Oñate was a Spanish conquistador and explorer who led the first Spanish colonization of New Mexico in 1598. Hernando de Soto's nephew, Luis de Moscoso Alvarado, led an expedition in 1542 that was the first to cross the Mississippi River. Finally, Álvar Núñez Cabeza de Vaca was a Spanish explorer and one of the first Europeans to explore the northern coast of the Gulf of Mexico.