MEXICO CITY.- Construction of the Metro Collective Transport System tunnels have benefited Mexican Archaeology by uncovering vestiges found in Mexico City. In 4 decades more than 20,000 objects from Prehispanic, Colonial, and Modern ages have been recovered, allowing verify information from historical documents. Archaeologist Raul Arana, who worked in the first archaeological salvage tasks conducted by the National Institute of Anthropology and History (INAH) in 1967, when the first 2 Metro lines were being constructed, declared so. Explorations were performed at densely populated places that would have not been excavated in other circumstances, such as Izazaga Avenue and the Zocalo Square, mentioned the archaeologist at a conference presented as part of the 40 years of the Metro commemorations. At his lecture about the first participations of INAH in archaeological exploration at the Metro excavations, Arana recalled how the