What brought the Mayan civilization to its demise? Many custom research papers analyzed the possible reasons. Mel Gibson enumerated different factors (albeit in brief scenes) in "Apocalypto".

A number of custom research papers noted the Mayas for their art and architecture. Gibson showed it in the middle of the film, where a small group of captive tribesmen passed by elaborate structures and a step pyramid. The plot follows a young tribesman named Jaguar Paw whose village is attacked and burned by raiders. He manages to hide his pregnant wife and child in a cave before he is caught. He is brought to a Mayan city along with his fellow villagers. They are sacrificed and killed, but he managed to  escape and return to where his village once stood.

I thought that Gibson's movie is simple until halfway; I find out that the movie is set during the decline of the Mayan civilization. What caused their downfall can be seen in glimpses: famine; warfare; shrinking populace; and the arrival of the Spaniards (led by Hernan Cortez). Gibson's attention to details is impressive; I was scared out of my wits during the sacrificing of young men to the sun god Kukulkan.

The movie is hard to watch at times because of its graphic depiction of how people are killed (in such a manner) during those times, but Gibson can't be criticized for it; what he showed is the closest thing to what really happened a millennium ago.