in the area and little information as to how this area was affected. It was officially declared a town in 1861, with the name of Villa de Mateos Tequisquiapan. During the Mexican Revolution, army loyal to Villa, Carranza and Obregón passed through but no battles were fought in the municipality. However, these armies did sack area haciendas and other locations, mostly for supplies. The Centenario Dam was inaugurated in 1910. Venustiano Carranza visited the thermal springs of the area before heading to the city of Querétaro to sign the 1917 Constitution. This Mexican president also declared the town as the “geographic center of the country.” There is a monument in the town to this effect; however, today the geographic center is considered to be in Zacatecas . Shortly after the end of the Revolution, there was political instability in the state and Tequisquiapan was designated as the provisional capital in 1920. Although its first municipal status was gained in 1861, but its current municipal organization was not formalized until 1939. The growing of grapes in the municipality begin in the early 1960s, with the planting of 120,000 vines for wine grapes in the community of San José Buenavista by the Sofimar enterprise, affiliated with Martelli in France. Initial varieties were ugni blanc (used for brandy), cabernet sauvignon and Grenache, for reds, whites and rosés. The latter 20th century saw significant population growth, as the town transformed from a small traditional farming village to a popular weekend getaway. This growth has also been spurred by the growth of the nearby industrial city of San Juan del Río . Since 1950, the population of the municipality has grown from 10,877 to 54,929 in 2005. However, the indigenous population has severely decline, from an indigenous majority in the 19th century to only 120 people speaking an indigenous language in the entity as of 2005. In 2007, the PRD municipal president Noé Zárraga, was shot twice by unknown persons. Environment The territory is located in the Mexican Plateau on the southeast side of the Sierra Gorda. The land is relatively flat with rolling hills and small valleys which are mostly farmland. The terrain contains both volcanic and sedimentary rock due to its geological history. The elevations in the area are small with mostly porous rock. In some areas there are quartz and opal deposits. In other areas, there are deposits of rhyolite and pearlite.