Finding all the good land was taken, the first Aztecs settled on a swampy island in 1325, in the center of Lake Texcoco.
Since they settled on swampy land, they had limited land for farming, and built Chinampas, floating rafts with soil where crops could be planted.
Because traveling to and from their city was hard, they also built causeways, raised roads on water, and canals that crisscrossed the city.
One of the main factors of the Aztec's rise to power was war. They were hostile and the people they conquered were forced to send in payments for tribute, and the riches that came were important to their economy.
Trade was also vital in their rise. Merchants brought goods all around the empire, which had a giant trade network. Some merchants were even spies, and kept the rulers informed on what was happening.
Tenochtitlan was a giant empire that was able to rise to power and create and do astonishing things.