The domestication of crops and animals created an abundance of food and livestock, which allowed people to take on new social roles and to develop specialized occupations. As cities emerged, they became hubs of a universal human activity: trade. These cities were home to priests who interpreted the nature of our world, as well as a nobility from which kings emerged.

The differences in the development and application of three different kinds of technologies — the wheel, writing and communications systems, and calendars — capture this essential nature of human adaptability.

Before their encounters with other world peoples that began in 1492, societies in Mesoamerica and the Andes did not use wheels. In Mesoamerica there were no large animals like horses or oxen to domesticate as beasts of burden, so there was no way to power wagons or chariots. In the Andes, domesticated llamas and alpacas served as pack animals and were a source of wool and meat. But in the most densely settled, cultivated, and developed areas, the terrain was too difficult for wheeled transportation. Instead Andean peoples developed extensive networks of roads that navigated steep changes in altitude, supported by elaborate suspension bridges made from woven vegetable fibers.

Peoples of the Americas also did not develop an alphabet or character-based writing systems, but this did not mean they did not communicate or record information. Peoples of the Americas spoke thousands of languages. Mesoamericans, beginning with the Olmecs (1500–400 B.C.E.), used pictographic glyphs similar to those of ancient Egyptian writing to record and communicate information. Later civilizations continued to adapt these systems. The Aztecs produced hieroglyphic books written on paper or deerskin.

The Andean innovation for recording information was particularly remarkable. The khipu (KEY-pooh) was an assemblage of colored and knotted strings. The differences in color, arrangement, and type of knot, as well as the knots’ order and placement, served as a binary system akin to a contemporary computer database. Khipus were used to record demographic, economic, and political information that allowed imperial rulers and local leaders to understand and manage complex data.

Mesoamerican peoples used a sophisticated combination of calendars. These were based on a Calendar Round that combined a 365-day solar calendar with a 260-day calendar based on the numbers thirteen and twenty, which were sacred to peoples of Mesoamerica. Annual cycles are completed when twenty 13-day bundles converge with thirteen 20-day bundles. Together with the solar calendar, these formed a fifty-two-year cycle whose precision was unsurpassed in the premodern world.