<human>: The Pre-Columbian era refers to all period subdivisions in the history and prehistory of the Americas before the appearance of significant European and African influences on the American continents, spanning the time of the original arrival in the Upper Paleolithic to European colonization during the early modern period.  While technically referring to the era before Christopher Columbus' voyages of 1492 to 1504, in practice the term usually includes the history of American indigenous cultures until Europeans either conquered or significantly influenced them. "Pre-Columbian" is used especially often in the context of discussing the pre-contact Mesoamerican indigenous societies: Olmec; Toltec; Teotihuacano' Zapotec; Mixtec; Aztec and Maya civilizations; and the complex cultures of the Andes: Inca Empire, Moche culture, Muisca Confederation, and Canari.  The Norte Chico civilization (in present-day Peru) is one of the defining six original civilizations of the world, arising independently around the same time as that of Egypt. Many later pre-Columbian civilizations achieved great complexity, with hallmarks that included permanent or urban settlements, agriculture, civic and monumental architecture, and complex societal hierarchies. Some of these civilizations had long faded by the time of the first significant European and African arrivals (ca. late 15th-early 16th centuries), and are known only through oral history and through archaeological investigations. Others were contemporary with the contact and colonization period, and were documented in historical accounts of the time. A few, such as the Mayan, Olmec, Mixtec, and Nahua peoples, had their own written languages and records. However, the European colonists of the time worked to eliminate non-Christian beliefs, and burned many pre-Columbian written records. Only a few documents remained hidden and survived, leaving contemporary historians with glimpses of ancient culture and knowledge.  According to both indigenous American and European accounts and documents, American civilizations before and at the time of European encounter had achieved great complexity and many accomplishments. For instance, the Aztecs built one of the largest cities in the world, Tenochtitlan, the ancient site of Mexico City, with an estimated population of 200,000. American civilizations also displayed impressive accomplishments in astronomy and mathematics. The domestication of maize or corn required thousands of years of selective breeding, and continued cultivation of multiple varieties was done with planning and selection, generally by women.  Inuit, Yupik, Aleut, and American Indian creation myths tell of a variety of origins of their respective peoples. Some were "always there" or were created by gods or animals, some migrated from a specified compass point, and others came from "across the ocean". CANNOTANSWER

Answer this question "What else did they do during that time?" by extracting the answer from the text above.
<bot>: the Aztecs built one of the largest cities in the world,