What year were the Aztec defeated by the Spanish, headed by Hernán Cortés?

Explanation

The Aztec were a Mesoamerican people from central Mexico with a rich mythology and cultural heritage. They were known for their religious human offerings which took place in great numbers. The Aztec built the city Tenochtitlan in the same location as where Mexico City stands today. They also called themselves Mexica, from where the country name 'Mexico' is derived. Today, the term 'Aztec' is used to cover all people who through trade, customs, religion and language were connected to the Mexica. The Aztec were defeated by the Spaniard Hernán Cortés in 1521.