Aztec Calendar stone or Sun stone, National museum of Anthopology, Mexico City, a photo by Mikey Stephens on Flickr.
The Aztec calendar is a system that was used by the Aztecs as well as other Pre-Columbian peoples of central Mexico, such as the Maya.
The calendar offered of a 365-day calendar cycle.
The Aztec calendar stone, Mexica sun stone, Stone of the Sun (Spanish: Piedra del Sol), is a monolithic sculpture that was excavated in the Zócalo, Mexico City's main square in 1790. It was discovered whilst Mexico City Cathedral was being repaired.
The stone is around 12 feet (3.7 m) across and weighs about 24 tons.
The Aztec knowledge of geometry enabled them to carve the stone symmetrically and their knowledge of mechanics enabled them to move the stone from its quarry to its final destination.
The figure in the center may be the sun god or sea god.
There is little left of Aztec history. "The codices that documented the events of Spanish contact repeatedly describe the demand by the Spaniards for the Aztecs to end the human sacrifices that were committed before their eyes. The Aztecs routinely refused despite these pleas," says worldmuseumofman.org.
"What the Spaniards saw in the Aztec society was beyond anything they could have ever seen in their former experiences. Because of this, the destruction of all traces of Aztec society by Cortes and his army was complete. Aztec artifacts are amongst the rarest of Mesoamerican Indian cultures because little survived their annihilation."