Answer:
The Pre-Columbian empire that European explorers "discovered" along the west coast of South America when they first arrived was the Inca Empire.
The Inca Empire was the largest empire in pre-Columbian America, and it was located in the Andes mountains of South America, primarily in the present-day countries of Peru, Ecuador, Bolivia, and Chile. The Inca civilization was highly advanced, with sophisticated systems of agriculture, architecture, and engineering. The Inca Empire was also known for its extensive road network, which allowed for efficient communication and trade throughout the empire.
The Inca Empire was at the height of its power and influence when the Spanish arrived in the early 16th century. The Spanish conquistadors, led by Francisco Pizarro, quickly conquered the Inca Empire and brought about its downfall. The conquest of the Inca Empire led to the introduction of Spanish culture and language to the region, and it had a profound impact on the history and development of South America.