The Aztec Calendar Stone, also known as the Sun Stone, is a large monolithic sculpture created by the Aztec civilization in the early 16th century. It measures about 3.6 meters (12 feet) in diameter and is made of basalt. The stone features intricate carvings that represent various aspects of the Aztec cosmology, including the five worlds of the sun and the gods associated with each. Discovered in 1790 in Mexico City, the stone is often mistakenly thought to be a calendar. Instead, it serves as a ceremonial monument that reflects the Aztec understanding of time and the universe. Today, it is housed in the National Museum of Anthropology in Mexico City.