Deep within the Calakmul Biosphere Reserve, researchers have used advanced aerial imaging to locate the Temple of the Celestial Monkey, a Pre-Classic Maya structure. The temple is topped by a platform containing three large stone masks of primate deities, which the Maya associated with the arts, writing, and the movement of the stars. This temple predates the more famous urban centers of the region, suggesting a much earlier complex social hierarchy.
Excavations at the base of the staircase revealed a cache of obsidian blades and jade beads, indicating that the site was a major destination for ritual pilgrimage. The orientation of the temple's main axis aligns perfectly with the rising of the Pleiades constellation during the spring equinox, confirming its role as a sophisticated astronomical observatory.