Why did the Spanish attack the Aztecs?

Hello. There were a few reasons why the Spanish attacked the Aztecs. The Spanish were astonished by the city when they stepped in. It was highly wealthy and large. They strongly desired the gold, silver and jewels. Another, was to seize control on the way they lived. They wished to change the Aztec way of life and convert them to Catholic, as they were very upset and overwhelmed when they saw people being sacrificed in inhumane brutal ways. Thirdly, they felt they had to make that place theirs as it was their discovery.