Final answer:
Vázquez de Coronado's main achievement as an explorer was discovering the Grand Canyon and several other significant places in the southwestern U.S., not the Seven Cities of Gold.
Step-by-step explanation:
The main achievement of the Spanish explorer Vázquez de Coronado was the discovery of the Grand Canyon and several other important landmarks in the southwestern U.S. While he was hoping to find the fabled Seven Cities of Gold, his expedition didn't locate these. However, it significantly expanded Spain's knowledge of the New World geography. He led one of the largest European expeditions ever to explore North America.
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