Final answer:
The fall of the Mayan civilization was the result of various factors including epidemic diseases, invasions, natural disasters, internal revolutions, environmental degradation, and increased warfare for resources. The Spanish conquest also played a key role in the decline of their society. However, the Maya people did not vanish and still inhabit regions in Central America.
Step-by-step explanation:
The cause of the fall of the Mayan civilization has puzzled scholars for many years. This once vibrant culture underwent a serious decline around the ninth century CE due to a combination of factors, such as epidemic diseases, invasions, natural disasters, internal revolutions, and environmental degradation. Among the evidence that points to possible causes are increased warfare and competition for resources, malnutrition, lack of food, and climate change which likely forced people to abandon their cities and led to the civilization's eventual collapse.
By the Post-Classic period, the Maya civilization had become more fragmented into independent city-states, and it had to endure multiple invasions by the Spanish beginning in 1511 CE. The conquest, along with the destruction of Mayan texts and cultural knowledge by the Spanish, greatly contributed to the decline of Mayan society. Nonetheless, it's important to note that though the classical cities were abandoned, the Maya people did not disappear and their descendants continue to live in the region today.