Who conquered Tenochtitlan in 1521 and in what ways did the newcomers differ from the Aztecs?

Tenochtitlan was conquered in 1521 by Spanish conquistador Hernán Cortés and his forces. The newcomers differed from the Aztecs in several ways, including their advanced military technology, such as firearms and steel weapons, as well as their use of horses in battle. Additionally, the Spaniards had alliances with other indigenous groups who opposed Aztec rule, and they brought diseases like smallpox, which devastated the Aztec population. These factors collectively contributed to the downfall of the Aztec Empire.