The Aztecs decide to settle in Mexico because their god told them to move south. When they did, they found a piece of land, but all the good parts of the lands were taken by the other tribes, and the Aztecs had try to live in an area that holds a lot of snakes. The Aztecs thought their god abandoned them, but then their god spoke to them again. The Aztecs did as they were told to, to keep going south until they see a hawk landing on a cactus growing out of a rock. Later, the Aztecs did see a hawk landing on a cactus growing out of a rock, and that's why they settled on Tenochtitlan, a land in the middle of lake Texcoco.