El Bajío (the lowland) is a cultural and geographical region within the central Mexican plateau which roughly spans from north-west of the Mexico City metropolitan area to the main silver mines in the northern-central part of the country. This includes (from south to north) the states of Querétaro, Guanajuato, parts of Jalisco (Centro, Los Altos de Jalisco), Aguascalientes and parts of Zacatecas, San Luis Potosí and Michoacán. Located at the border between Mesoamerica and Aridoamerica, El Bajío saw relatively few permanent settlements and big civilizations during Pre-Columbian history, being mostly inhabited by nomadic tribes known to the Aztecs as "The Chichimeca" peoples (the barbarians), another Nahua group from whom the Toltec and the Aztecs were probably descended. The tribes that inhabited El Bajío proved to be some of the hardest to conquer for the Spanish, but due to its strategic location in the Silver Route, it also drew prominent attention from the Spanish crown and some of the flagship Mexican colonial cities had to be built there, such as Guanajuato and Zacatecas. The abundant mineral wealth and favorable farming conditions would soon turn the region into one of New Spain's richest. At the beginning of the 19th century, El Bajío was also place to the ignition of the Mexican War of Independence, and saw most of its battles during the initial phase of the war, including the Cry of Dolores, the storming of the Alhóndiga de Granaditas and the Battle of Calderón Bridge. Nowadays, the region features one of the strongest economies in Mexico and Latin America, drawing both domestic investment from the adjacent, industry-heavy State of Mexico, as well as foreign companies in seek for cheap specialized labour and decent infrastructure (mostly American, Japanese and to some extent, European vehicle and electronics companies). The largest cities of the Bajío are Guadalajara, León, Santiago de Querétaro, and Aguascalientes. History of El Bajío Recent archaeological studies of the Bajío have discovered an extensive, historic cultural tradition unique to the region, particularly along the flood plains of the Lerma and Laja rivers. The Bajío Culture flourished from 300 to 650 CE, with cultural centers ranging from El Cóporo in the far north of Guanajuato to Plazuelas in the far south west. More than 1,400 sites have been discovered throughout the state of Guanajuato, with only the sites of Cañada de la Virgen, El Cóporo, Peralta, and Plazuelas having received extensive study. This