Stone of the Sun

Mexica Sun Stone at the Museo National de Anthropologia, Mexico City. Personal photograph. 22 November 2009. 

This stone was discovered on December 17, 1790 under the Zocalo, Mexico City's main square, just several miles away from its current residence at the National Anthropology Museum. According to Encyclopedia Britannica, the stone weighs 25 tons and spans 12 feet in diameter. The stone was originally believed to be an Aztec calendar because it contains references to dates and seasons. The museum, however, describes the stone as an unfinished sacrificial altar of the Mexicas, the immediate predecessors of modern Mexicans. By that interpretation, the altar, now hung vertically, was intended to lie flat on the ground for sacrifice.