Archaeologists have discovered the ruins of an 800-year-old Aztec pyramid in the heart of Mexico City that could show the ancient city is at least a century older than previously thought.

read a paper on the Aztec Calendar, or Mexican calendar stone, from which an insight has been obtained to the extent of the astronomical knowledge of the Aztecs. View Full Article in Timesmachine ...

Housed within the facility’s 22 rooms are artifacts, including the famous Aztec Calendar Stone ... Balloon Flight over Teotihuacan, from Mexico City ...