Evidence of the Maya civilization's religious beliefs is extensive.
Some gods had different aspects based on four directions. There were thirteen gods of thirteen heavens and nine gods of nine underworlds. Natural elements, stars and planets, numbers, crops, days of the calendar and periods of time all had their own gods.
The Popol Vuh. This has the world created from nothing by the will of the gods. Man was made unsuccessfully out of mud and then wood before being made out of maize and being assigned tasks which praised the gods - silversmith, gem cutter, stone carver, potter, etc. Some argue that the Maya did not believe in art per se; all of their works were for the exaultation of the gods. The Popul Vuh then tells of the Hero Twins and their adventures in defeating the lords of Xibalba, the underworld.
The last thirteen creator gods (built humanity from maize):
http://www.geocities.com/athens/academy/7286/popolvuhmain.html