Developments in the Americas

Emerged in the 700s or 800s in the Mississippi River Valley as the first large-scale civilization in North America.
Built massive earthen mounds for architecture, the largest being Cahokia in southern Illinois, which reached up to 100 feet tall.
Organized into a rigid, matrilineal social hierarchy ruled by a chief called the Great Sun, followed by priests and nobles, a lower class of commoners, and enslaved prisoners of war.
Abandoned Cahokia around 1450 and other major cities by 1600 due to weather extremes/crop failures or European diseases.

Emerged in the dry southwestern United States, developing efficient systems to collect, transport, and store water.
The Chaco constructed multi-room housing structures from stone and clay, while the Mesa Verde built multi-story homes into sandstone cliffs.
Both groups declined in the late 13th century as the regional climate became drier.

Reached their peak between 250 and 900 C.E. across southern Mexico, Belize, Honduras, and Guatemala, housing up to 2 million people across roughly 40 cities.
Governed through decentralized city-states ruled by kings (or women when no male heir was available) who claimed descent from gods.
Fought neighboring city-states primarily to extract tribute payments and capture human sacrifices rather than to control territory.
Incorporated zero into their number system, created a complex writing system, manufactured rubber from plants, and built precise observatories atop pyramids such as Chichen Itza to design an accurate calendar.

Migrated to central Mexico in the 1200s and established their capital, Tenochtitlán, on an island in Lake Texcoco in 1325.
Developed infrastructure including aqueducts, a 150-foot Great Pyramid, and floating gardens called chinampas to produce crops.
Established a theocracy led by an emperor called the Great Speaker, supported by land-owning military nobles, scribes, healers, craftspeople, luxury merchants called pochteca, peasants, soldiers, and enslaved people.
Implemented a tribute system requiring conquered provinces to submit practical goods, luxury items, and military service.
Practiced human sacrifice and bloodletting as religious atonement to the gods and as a demonstration of imperial power.
Suffered from late 15th-century decline caused by limited technology (lack of wheeled vehicles and pack animals), overexpansion, and resentment from subject tribes prior to the arrival of Spaniards in 1519.

Initiated in 1438 by Pachacuti, who conquered lands near Cuzco, Peru, creating an empire that stretched from Ecuador to Chile and was later consolidated by Huayna Capac by 1493.
Divided into four administrative provinces, each featuring its own governor and official bureaucracy.
Substituted tribute payments with the mit'a system, a mandatory public service requirement for men aged 15 to 50 to construct roads and perform agricultural labor.