The chapter focus on the Mesoamerican calendar which is demonstrated by the fact that the numbers that define it are often considered ideal when it comes to certain architectural elements and they could even influence the number of offerings made at religious ceremonies. Mesoamericans oriented their structures using the sky as a reference to mark the importance of certain canonical dates. Additionally, all Mesoamerican deities possessed a calendrical name corresponding to a date within the ritual 260-day calendar in which an important event occurred concerned with that particular deity. Perhaps the least known aspect of the significance of the Mesoamerican calendar is the relationships between the orientation of architectural structures, landscape and the measurement of time. The Mesoamerican calendar, considered to be the work of the gods, was highly relevant to every aspect of society. The practice of orienting buildings, in force for several millennia, could be considered another salient cultural manifestation that defined Mesoamerica.