The Aztec Triple Alliance (c. 1428–1521) built a tributary empire, a sophisticated water-management infrastructure, and one of the largest cities in the world — before the Spanish conquest reduced it to rubble within two years. The entry asks what the Aztec state actually was as a political-economic structure, independent of how it ended.
When the Spanish arrived in 1519, they found a city bigger than any in Europe, floating on a lake, fed by aqueducts, and governed by an administrative system that extracted tribute from hundreds of subject polities. Understanding what the Aztecs built — before what happened to them — is where the history begins.