Spanish Conquistador Hernán Cortés was inspired as a boy by the tales of Christopher Columbus discovering a new world to seek his own adventures in the West. He barely escaped death in 1519, by discovering a conspiracy to kill him. His dying would have led to defeat of this Spanish invasion, giving Aztecs time enough to regroup. The Aztecs could have easily learned how to manufacture firearms from captured Spaniards. If they did, they could have survived as a powerful Aztec nation, possibly even into the 20th century. (Hat tip, historian Al Carroll.) But Cortes conquered the Aztecs in 1521.