Jean Filliozat of the Ecole Francaise, a leading western authority on Indian cosmology and astronomy, interpreted the symbolism of the temple. The temple sits on a rectangular base and rises in five levels and is crowned by five main towers. One hundred four smaller towers are distributed over the lower four levels, placed so symmetrically that only 33 can be seen from the center of any side. Thirty-three is the number of gods who dwelt on Mount Meru. Phnom Bakheng's total number of towers is also significant. The center one represents the axis of the world and the 108 smaller ones represent the four lunar phases, each with 27 days. The seven levels of the monument represent the seven heavens and each terrace contains 12 towers which represent the 12-year cycle of Jupiter. According to University of Chicago scholar Paul Wheatley, it is an astronomical calendar in stone.