The primary cause of the collapse of the Mayan civilization is believed to be a combination of environmental factors, warfare, and societal disruptions. Prolonged drought during the late Classic period negatively impacted agriculture, leading to food shortages and economic decline. Additionally, internal conflicts and warfare among city-states exacerbated the crisis, contributing to social instability. The gradual decline, starting around the 9th century, resulted in abandoned cities and a significant decrease in population, marking a mysterious but impactful end to one of ancient Mesoamerica's most advanced civilizations.