The Aztecs lived in the Valley of Mexico, a high plateau with fertile soil from volcanoes. They were skilled engineers and architects, building cities on islands in lakes connected by causeways and aqueducts. The Aztec empire grew through warfare to control Mesoamerica by 1500. Their absolute monarchy was advised by councils but the king had ultimate power and collected tribute. The Aztecs were very religious and sacrificed people to please the gods. Society consisted of nobles and commoners who farmed or worked as artisans. The Aztecs excelled at engineering, arts, jewelry, and oratory despite having no strong written language.