Maya Civilisation

The Maya civilisation (2000 BC - 1500 AD) developed the only fully functional writing system in pre-Columbian Mesoamerica, independently invented the concept of zero, created the most accurate calendar of the pre-modern world, and built cities with sophisticated astronomical observatories, ball courts, and hydraulic systems. At their peak, Maya cities had populations of 100,000 — comparable to the largest cities of medieval Europe.