This inquiry provides students with an opportunity to evaluate a series of innovations by three complex civilizations— Maya, Aztec, and Inca. In examining the compelling question “What makes a complex society complex?” students explore how complex societies and civilizations adapt to and modify their environment to meet the needs of their people. Students use the social studies practices of Comparison and Contextualization as they work with sources related to the ancient writing developed by the Maya, specialized agricultural methods developed by the Aztecs, and transportation/communication networks developed by the Inca. The goal of this inquiry is to provide enough background about these innovations and technological advancements to support students as they develop arguments about what makes societies complex.