What major empire developed in the Western Hemisphere?

The major empire that developed in the Western Hemisphere was the Aztec Empire, which thrived in present-day Mexico from the 14th to the 16th centuries. The Aztecs built a sophisticated society known for its impressive architecture, complex social structure, and vibrant culture. They established their capital, Tenochtitlan, on an island in Lake Texcoco, which became one of the largest cities in the world at that time. The empire ultimately fell to Spanish conquistadors led by Hernán Cortés in 1521.