The causes for the Maya's decline are numerous, but one of the central causes is that the demands they placed upon their environment grew beyond the capacity of the land. At it's peak, there were about 15 million people occupying the Mayan world. Over-population of Mayan metropolises are suspected to have gone beyond levels that the Mayan political and social networks were able to support, resulting in social unrest and revolution. Frequent skirmishes by warring clans, such as the Toltec invasion of Chichen Itza, are suspected to have forced the Mayan populace to flee their cities. Recent studies have discovered evidence of severe droughts, deforestation, and a decline in large game animals that began around 800 A.D., coinciding with a sharp drop in new construction. Human bones found from this time show signs of severe malnutrition, which would have been a driving factor behind raids. While Maya civilization did go through a brief renaissance after this period, ongoing environmental constraints played a large role in their eventual decline.
By the time the Spanish Conquistadors arrived, most of the large Mayan sites had been all but abandoned for hundreds of years. Most of their cities had fallen into ruin and were being overtaken by jungle. The Maya people had splintered into small villages and towns, losing the complex social strata and rituals that supported this great civilization at its apex.
The Spanish colonization of the Maya officially began in 1521 when Francisco de Montejo petitioned the King of Spain for the right to conquer the Yucatan. It took the Spanish 170 years and a number of expeditions to finally subjugate the Maya peoples, much longer than their campaigns against the Aztecs and Incas. The last Mayan stronghold of Tayasal in Guatemala fell in 1697. Aiding in the Spanish conquest was the introduction of European diseases, which decimated Mayan populations since they had developed no immunity. The primary goal of the Conquistadors within the Americas was to locate vast quantities of gold and silver. Trace amounts of these precious metals were found that had been transported to the Mayan kingdom via their various trade routes from Columbia and Ecuador, but the Spanish did not find the riches that they had hoped for.
The Spanish colonization entailed forced labor and mandatory conversion to Christianity. Those Maya who refused to give up their pantheistic religious practices were arrested and tortured for heresy. Mayan artifacts were actively destroyed and all but a few of their sacred texts burnt. However, in 1820, the colonies broke from Spain, and the pressure for the Maya to abandon their culture was gone. Today, many of their descendants living throughout Central America still speak an evolved version of the Mayan language and have managed to retain some of the ancient Mayan cultural practices.