The cave recently discovered underneath the Pyramid of the Sun in Teotihuacan, Mexico, is analyzed both according to historical written sources and reports of cults to cave deities, prominent in Mexico for millennia. Different cave rites are discussed in an effort to determine the function of the grotto. The Teotihuacan cave is compared with the mythical Chicomoztoc, Seven Caves, place of creation in ancient Mexican mythology. The author suggests that the cavern may have determined the site for the building of the Pyramid of the Sun and that later Aztec accounts of rulers being buried underneath the pyramid may have been based upon fact.