La Constancia Mexicana is a textile factory from downtown Puebla, in the state of Mexico. The factory was the first textile mill to integrate automatic machinery into the production process. The factory was built within Santo Domingo Hacienda, which had an established hydrological infrastructure useful to textile manufacturing. The hacienda's architecture was updated to the 19th-century style, giving it a unique appearance. Thus, the factory introduced a new architectural style along with the new machinery. This site was added to the UNESCO World Heritage Tentative List on December 6, 2004 in the Cultural category.