Mexico Citys Zócalo, the Plaza de la Constitución, is located at the site of Tenochtitlans original central plaza and market, and many of the original calzadas still correspond to modern city streets. The Aztec calendar stone was located in the ruins. This stone is 4 meters in diameter and weighs over 20 tons. It was once located half-way up the great pyramid. This sculpture was made around 1470 under the rule of King Axayacatl, the predecessor of Tizoc, and is said to tell the history of the Mexicas and a prophecy for the future.[29]