I studied mayan art history in college and will give it a shot. Pre-columbian dudes with big noses controlled waterways through the jungles of the Yucatan Peninsula defining their territory, placement in trading hierarchy, overall social status between tribes. They played a soccer like game with a rubber ball and carved stone statues of their leaders called stelae. All existing knowledge of their cultures is interpretated primarily through these carvings and basic anthropological methods such as pottery shard identification. Their leaders were viewed as gods; to emulate a certain flat forehead characteristic of preceding ruling dynasties, they would place their babies in cribs that pressed their heads flat with stones. After wars and ball games the losing tribes were put to death atop intricate bloodletting temples; this was an extremely high honor and losers offered themselves willingly. It is thought they may have even had a lottery for bloodletting "offerees" within individual tribes- the families of the sacrificed would become prominent and essentially be set for life. One tribe raised ducks that ate poisonous toads; the poison settled in the meat; and once a year, everyone in the tribe would eat duck and get really high for a month or so as part of their belief system in an attempt to connect with dead family members and ensure safe passage to the otherworld. These tribes most likely disappeared because of the following factors.
A. Overland jungle routes de-emphasized the river trading routes to the coast and their communities high up on canyon walls became a moot point.
B. Agricultural difficulties such as an extended drought may have forced them to move.
C. Aliens.
One last note: Pretty much all mayan culture was interpreted incorrectly biased by spanish explorers and settlers who linked imagery from stelae to serpent mythology in an attempt to paganize their religious beliefs as anti-christian stemmed from the devil. Mayan culture has and is currently being reclassified since the spanish bias slant was realized over the past few decades.
