The ancient Mexican metropolis of Teotihuacan is one of the most critical archaeological sites in the world for understanding the early human experience with cities.  During its apogee (ca. 1-550 CE), Teotihuacan was the largest city in the western hemisphere; it is also currently a UNESCO World Heritage Site and is visited by millions of tourists annually.  Some of the urban characteristics that make Teotihuacan stand out for early cities are (1) the intense amount of craft production and exchange evidenced by artifacts from the site; (2) the fact that most of the city’s inhabitants lived in large, multi-family apartment compounds—possibly unique for the pre-modern world; and (3) its highly planned layout along an orthogonal plan tethered to a central artery called the Street of the Dead by the later Aztecs.  The current project focused on the Tlajinga district, a southern cluster of neighborhoods (Figure 1), was directed by David Carballo (Boston University), Kenneth Hirth (Penn State), and Luis Barba (Mexico’s National Autonomous University, UNAM) with goals of addressing all three of these characteristics.

Major project initiatives included two seasons of excavations at apartment compounds and along the southern Street of the Dead and the mapping of the entire district (approximately 1 km²) using digital topography, photogrammetry, and geophysical prospection, undertaken over four different seasons (Figure 2).  Material science applications included study of the chemistry of living floors and human bones, sediment micromorphology, and detailed AMS radiocarbon dating—this last making the Tlajinga district one of the best dated parts of Teotihuacan.  Investigations were collaborative and involved students and faculty from the US, Mexico, and Germany.

Results of the project included the detailed documentation of a large obsidian workshop at apartment compound 17:S3E1 (Figure 3).  Obsidian was one of the major commodities at Teotihuacan, as in the absence of metals it was used for most cutting activities.  Compound 17 is the first obsidian workshop of its kind to be subject to detailed excavations and analyses, and shows that inhabitants of the periphery of the city could specialize in utilitarian forms of production in order to access other commodities that circulated within the urban and interregional economies.  Excavations at a second apartment compound, Compound 18:S3E1 (Figure 4), were aimed at investigating the central courtyards, since these are locations where group activities including domestic rituals took place.  These excavations also recovered deep stratigraphic deposits that permit us to understand the chronology of construction in the area, and how apartment compounds emerged as an urban housing type from smaller and simpler houses, made of perishable materials.  Finds at both compounds included imported items, such as marine shell, or more elaborately manufactured objects, such as a sculpted stone face and finely painted ceramics.  These attest to the level of access that Tlajinga’s occupants had within Teotihuacan’s economy, whereas their peripheral location in the city and more simply constructed homes denotes their common or working-class status.  

At the broader levels of the district and city as a whole, results of the project demonstrate how a formerly more rural area became part of an urban periphery.  This included the extension of the city’s central artery, the Street of the Dead, southward through the district, where excavations and micromorphology of sediments show that hard volcanic tuff substrate was cut approximately 40 m wide for over 500 m (Figure 5).  This would have therefore represented a major urban expansion project that necessitated the coordination of hundreds of people in the district, whereas the placement of apartment compounds and the construction of relatively simple retaining walls next to the Street of the Dead indicates the operation of more local labor efforts in infilling the urban landscape.

Project results are relevant to broader study of the global history of urbanism, now the dominant settlement type on the planet.  They have and are continuing to be disseminated widely through academic and popular publications, through involvement of project collections in a major museum exhibit set to tour the US beginning in fall 2017, and through multi-media efforts including video and radio podcast on NSF sites, with a few links below.

https://science360.gov/obj/video/44bbe233-9c0c-4762-9716-bfbe52e16354/lessons-teotihuacan-beyond-pyramids

https://science360.gov/radio/episode/04d08d07-ead0-4c89-b072-816d9c0ef5b5/new-nsf-podcast-dig-archaeologist-david-carballo-describes-life-working

Finally, the project involved close international collaboration between researchers in the US and Mexico, as well as training and early career development for women and underrepresented minorities in science.

Last Modified: 06/11/2017
Modified by: David M Carballo