Zócalo () is the common name of the main square in central Mexico City. Prior to the colonial period, it was the main ceremonial center in the Aztec city of Tenochtitlan. The plaza used to be known simply as the "Main Square" or "Arms Square", and today its formal name is Plaza de la Constitución (Constitution Square). This name does not come from any of the Mexican constitutions that have governed the country but rather from the Cádiz Constitution, which was signed in Spain in the year 1812. Even so, it is almost always called the Zócalo today. Plans were made to erect a column as a monument to independence, but only the base, or zócalo (meaning "plinth"), was built. The plinth was buried long ago, but the name has lived on. Many other Mexican towns and cities, such as Oaxaca, Mérida, and Guadalajara, have adopted the word zócalo to refer to their main plazas, but not all. It has been a gathering place for Mexicans since Aztec times, having been the site of Mexican ceremonies, the swearing-in of viceroys, royal proclamations, military parades, Independence ceremonies, and modern religious events such as the festivals of Holy Week and Corpus Christi. It has received foreign heads of state and is the main venue for both national celebrations and national protests. The Zócalo and surrounding blocks have played a central role in the city's planning and geography for almost 700 years. The site is just one block southwest of the Templo Mayor, which, according to Aztec legend and mythology, was considered the center of the universe. Description The modern Zócalo in Mexico City is 57,600 m2 (240 m × 240 m). It is bordered by the Mexico City Metropolitan Cathedral to the north, the National Palace to the east, the Federal District buildings to the south and the Old Portal de Mercaderes to the west, the Nacional Monte de Piedad building at the north-west corner, with the Templo Mayor site to the northeast, just outside view. In the centre is a flagpole with an enormous Mexican flag ceremoniously raised and lowered each day and carried into the National Palace. There is an entrance to the Metro station "Zócalo/Tenochtitlan" located at the north-east corner of the square but no sign above ground indicates its presence. History Pre-conquest Prior to the conquest, the area that the occupies was open space, in the center of