Which country had explorers who led expeditions into the lands of the Aztecs and Incas in North and South America? Who were these explorers?

The country that had explorers who led expeditions into the lands of the Aztecs and Incas in North and South America was Spain. The explorers were Hernán Cortés and Francisco Pizarro.

Hernán Cortés was a Spanish Conquistador who led an expedition that caused the fall of the Aztec Empire. Cortés was a part of the generation of Spanish colonizers that began the first phase of the Spanish colonization of the Americas.

Francisco Pizarro was a Spanish conquistador who led an expedition that conquered the Inca Empire. He captured and killed Incan emperor Atahualpa, and claimed the lands for Spain.