and social events with the costs and efforts associated with them rotated and shared among the various "barrios" or traditional neighborhoods. Among the important shared festivals, there are Carnival, the Vaniloquio, when the bells of the city's churches ring in coordination, Holy Week, La Bajada, when the image of the Virgin of the Remedies comes down the pyramid to visit the various neighborhoods and the most important, the feast day of the Virgin of the Remedies on 8 September. These and other traditions have roots in the pre Hispanic period. Many Cholutecans still use their pre-Hispanic surnames, such as former town stewards Raymundo Tecanhuehue and Humberto Tolama Totozintle. This is because a number of the old Indian nobility was allowed certain privileges after the Conquest. The town chronicler still refers to the barrios as calpulli, the pre-Conquest political organization of neighborhoods. Another unifying factor is a straight street grid oriented in the cardinal directions. Most streets in the center are numbered with indications as to their location vis-à-vis the center, north, east, south or west. Outside the city center street names lose this system. Landmarks San Pedro is home to what is considered to be the main plaza or square the city, called the Plaza de la Concordia. In the morning, this plaza of Cholula is filled with vendors selling typical street food, sweets and handcrafted toys for children. On the west side of this plaza is the "Portales" (Portals). This is a commercial area framed by forty-six arches supported by Doric columns. These arches measure 170 meters long and are the longest in Latin American. (pedro his). The San Pedro municipal palace is located behind this commercial area, occupying a space which was called the Xiuhcalli, (House of Turquoise), where a council of nobles met in the pre Hispanic era. On the south side of the plaza is the Museum of the City of Cholula, housed in a structure called the Casa del Caballero Aguilar (House of the Eagle Knight), one of the oldest residential structures in the area. This museum was opened in 2001 after extensive restoration of the colonial era building by INAH, the city and the Universidad de las Américas-Puebla. This work restored the original floor plan and much of the carved stone work. The museum traces the habitation of Cholula from about 1000 BCE. Three rooms display pre Hispanic artifacts, two contains colonial era items