The Aztec Calendar stone is one of the most incredibly well-preserved relics of the Aztec Empire. Generally considered to have been chiseled in the early 1500's, it's intricate design is actually much more than tribal artwork of the period. It is a highly structured accounting of the cycles of time as perceived by these ancients.
The Calendar stone is massive, with a diameter of 12 feet, 3 feet thick, and weighing 24 tons. The stone was rediscovered in 1790 and is intricately tied to Mexican history. It is now part of the National Anthropology Museum in Mexico City.