By the Late-Classic Period, scurvy and other diet-related diseases were prevalent. Trade relations between most Maya city centers became stressed and eventually broke down. Quality of life decreased. A plagued society fell into turmoil from the resulting social conflict. And in 869 AD, hundreds of years after its rise to glory, Tikal, the first great Maya city center, ceased all construction. Within thirty years, Tikal was vacant. Maya birth rates declined, and eventually, nearly all lowland cities were abandoned. One city in particular, Tulum, was constructed during this time and managed to avoid the same fate as her sister cities, even thriving in the face of total annihilation, but we will explore that in more detail later on.

There is some speculation that a sudden environmental catastrophe, such as an earthquake, tidal wave or flood, could have caused the Classic cities' abandonment. Some investigators have even proposed that beings from another planet incited mass emigration. But more historians hypothesize that depleting resources (which negatively impacted the surplus used for trade), combined with the Toltec western invasion, were the main culprits. Salt production could not keep up with the demands of overpopulated southern cities. Trade networks became paralyzed due to lack of provisions. The people were sick and starving, so perhaps, they moved away.

The Post Classic Maya continued to build cities and inhabit northern sections of their territory for another five hundred years, but by the year 1200, even northern cities began to decline. Never again did their people regain the richness, abundance and splendor reached during the Classic Period. By the early 1500's, arriving Spaniards like Hernan Cortes, Hernandez de Cordoba, and Francisco de Montejo not only brought troops and missionaries with them, but also carried a host of new diseases, like smallpox, influenza and measles. Within the next century, 90 percent of Mesoamerica's populous would be dead, their culture having survived for nearly one thousand years.