The Aztecs lived in ancient Mexico for 400 years, constantly moving and practicing human sacrifice to please their gods. They eventually settled in the Valley of Mexico among other tribes, building canoes to fish and trade. To build their city, the Aztecs established a system of free public schools for all children, even girls and slaves, which was unprecedented. The schools trained students in different skills depending on their gender and social class, and specialized professions like engineering helped the Aztecs design impressive cities and floating gardens to solve food shortages.