World’s Biggest Man-Made Calendar: El Castillo At Chichén Itzá (Archive)
Contemplating the ancient pyramid at Mayan archeological site Chichén Itzá in the blazing Yucatán sunlight, Elizabeth Doerr was awestruck by the structure’s complexity. Chichén Itzá’s most famous structure was built to be the world’s largest calendar . . . at a time when calendars didn’t even exist!










