Some years ago, the project’s excavations discovered an adobe fragment with a red strip in a pit at the Plaza North of the Sun Pyramid Complex (see Results 2018-2019, located in Front F’s second “window”). The team decided to extract it as a block and took it to the laboratory.
Afterwards, an arduous process of consolidation and conservation was undertaken. Once a portion of the block was turned over, we were surprised to see it was painted with a design. It depicts two yellow feathered serpents with multicolored bellies (green, red, and black). Furthermore, it is remarkable that this is a very ancient piece, dating from around 250 AD.
This piece is exhibited at Teotihuacan Archaeological Park’s Site Museum. Come and visit! Here we share a few pictures of its inauguration. We thank all the attendees, the team in charge of the mural’s intervention, and the people who made this exhibition possible, especially Jesús Torres from the Department of Museums and Educational Communication at the Archaeological Site of Teotihuacan, and Rogelio Rivero Chong, Director of the Archaeological Site of Teotihuacan.
Author: Edsel Robles Translation: Yun Ge Editors: Thania Ibarra and Sol Téllez Photographs: Mayté Espinoza
The excitement of the visit from the Xochicalli School students
One week before, our PI, Dr. Nawa Sugiyama, informed us that we would be receiving special visitors at the Plaza of the Columns. Our primary visitors are researchers, but this time they would be preschool and high school students. At first, we were a little hesitant, because none of us had studied pedagogy before, but the enthusiasm of looking forward to meeting them, and our experience with family members of various ages encouraged us to accept the challenge of making a wonderful visit. As hosts, we want all our visitors to have a great experience in the field.
Preparing the work
Among all the archaeologists, we brainstormed and designed various activities for the visitors to empirically experience archaeology. The most essential part of archaeology is its excavations and studies based on the major discoveries; therefore, the main activity was to make a small contextual excavation. To make it real, we buried different materials in the artificial deposit beforehand, including ceramics, bones and shells. We intentionally exclude the obsidian to avoid cutting accidents. A 3 x 3 meters “archaeological grid”, delimited by stones, was marked out. To protect our visitors, anything that could cause the mishap was removed. We used sifted soil from our own excavations, and the modern artifacts were placed simulating archaeological contexts. The ceramic pieces we were able to obtain were made by Teotihuacan ceramists and have a similar appearance to archaeological artifacts, making this connection between the past and the present even more realistic.
Suggestions were also made for activities the children would undertake after the excavation, such as a field laboratory. Proposed ideas—including puzzles, stories, diagrams, and drawings—were submitted to a vote. We also communicated with family members to find out the preferences of the children based on their age. In the case of drawing pieces, our project artist, Ramiro Medina, made two proposals based on a modern Teotihuacan vase. The first proposal was for the preschool children, which consisted of coloring the vase. For the adolescents, the proposal was simply to place guide points for them to complete the rest of the drawing.
Staging
On Monday, July 14th, in the Plaza of the Columns at the Teotihuacan archaeological site, we finally met the students from Xochicalli School, located in the municipality of San Juan Teotihuacan.
The visitors included both second-year preschool and third-year high school students. Our goal was to share the project’s ongoing activities and to introduce the children to the pre-Hispanic heritage that surrounds them. By reaching out to elementary schools in the communities around the site, we hope to inspire local children—potential archaeologists and future residents of the area—to stimulate their interest in their cultural heritage. In doing so, they may become valuable allies in the preservation of the archaeological remains found throughout their communities.
To facilitate meaningful engagement, the students were divided into smaller groups. Three thematic stations were prepared for their visit: a tour of our archaeological excavations, a simulated excavation, and activities in the field laboratories.
“Those mounds you see”
The first activity was a guided tour of the ongoing excavations in the Plaza of the Columns. Students learned that many of the mounds and raised areas visible on the surface often correspond to ancient structures buried beneath the ground. In this area, for example, original floors and walls become visible after removing just a few centimeters of soil, allowing a glimpse into the architectural past hidden below the surface.
The Excitement of Excavation
The second station featured a simulated excavation designed to teach visitors about the importance of the archaeological record and how context helps us interpret the materials we uncover. This hands-on experience sparked a genuine sense of discovery among both the younger children and the teenagers. The children participated with great enthusiasm, guided by archaeologists Thania Ibarra and Sol Téllez, while the teenagers approached the activity more carefully, showing a greater attention to detail as they explored the different layers and contexts.
Debunking Myths
While the visitors participated in the excavation, conversations with the archaeologists continued. The young people raised questions about the dating of the materials and frequently asked about the role of heritage in modern society. Another recurring question among the various groups was what happens if a family member has archaeological artifacts or if there are remains on the property of an acquaintance. In response, the researchers explained that the INAH does not confiscate artifacts that people legally possess, nor are their properties at risk. The importance of not removing archaeological materials found in homes and land was discussed, as important data such as the context would be lost. The importance of contacting the INAH was emphasized, as it is the institute responsible for protecting the country’s heritage and enriching our knowledge of our past.
What’s next?
The third activity focused on demonstrating the post-excavation analyses carried out in our laboratories, including cleaning the excavation materials and assembling the broken pieces. This was the part of the visit that sparked the most enthusiasm among students of all ages.
Additionally, there was a Zooarchaeological lab where students learned about the important role animals played in the ancient city of Teotihuacan. Beyond their use as a food source, animals contributed fur, served as pets, and even inspired mural paintings, becoming characters in local stories and legends.
Finally, in the laboratory area, we had the participation of Ramiro, our project’s artist and draftsman. Using a modern made Teotihuacan style vase, the children had helped unearthed during the excavation, Ramiro recreated his work with the visitors, who, depending on their age, were asked to color or draw lines to reproduce the design of the pieces. This activity allowed the artist to observe the different attitudes and aptitudes of the participants. For the younger children, the researcher shared his observations with their parents and offered suggestions on how to nurture their children’s talents. With the adolescents, he provided immediate feedback to help them improve their drawing skills.
Connecting with Young People
The young people were told that Teotihuacan was a great city, home to different ethnic groups, seats of power, architectural periods, etc. From this, the adolescents developed different interests, such as: the most valuable materials, their fashions, trends in building decoration, and the types of construction.
Our Impressions
This activity turned out to be even more rewarding than we had imagined. The active participation of the students—along with the genuine interest shown by parents and teachers, and the wide range of questions and curiosities—demonstrated how deeply the city of Teotihuacan continues to resonate with its local communities. It also reminded us of the many secrets the site still holds, secrets that may one day help us answer those unresolved questions.
We eagerly look forward to welcoming more students from the surrounding communities to explore and connect with the great pre-Hispanic city of Teotihuacan.
We would like to thank Jesús Torres from the Department of Museums and Educational Communication at the Archaeological Site of Teotihuacan for his support in coordinating this visit, as well as Rogelio Rivero Chong, Director of the Archaeological Site of Teotihuacan.
SOCIETY FOR AMERICAN ARCHAEOLOGY 90TH ANNUAL MEETING
Come join us at the Society for American Archaeology’s 2025 conference in Denver, Colorado. This year some members of our team will present the following talk:
SUNDAY, APRIL 27
Symposium: Complex Human-Animal Interactions in the Americas
Room: Plaza Building Director’s Row H Time: 9:30 am
Nawa Sugiyama, Christine France, Erin Thornton, Edsel Robles, and Teresa Hsu—Household-Level Management of Small Game at Teotihuacan, Mexico: Zooarchaeological and Isotopic Proxies from Plaza of the Columns Complex.
On the surface, archaeology appears simple – go to an archaeological site, start digging down, and haul out all the ancient ‘stuff’ that you can find. But in reality, archaeology involves a great degree of precise and hard work, alongside careful planning and execution in day-to-day operations. Much of the work on an excavation starts even before the first shovel hits the dirt. From simply setting up the excavation early in the morning, to survey and mapping, to detailed sketches of soil layers, to tagging and bagging of site features and artifacts, to the eventual closing down of excavations in the late afternoon, archaeologists and fieldworkers with the PPCC adhere to a daily routine and procedures that ensure we are able to make the most out of each field day and accomplish as much as we can before the months-long field season comes to a close. In this blog entry, I will detail the ins and outs of archaeological excavations in one day at Teotihuacan, so you can get a sense of the work that goes behind digging up those old artifacts you might see in a museum or news article.
Waking up bright and early around 6:00 AM (for the daring, even earlier; for the especially daring, even later), the PPCC team prepares for departure to the field. After having breakfast and suiting up in our field apparel, which usually consists of long-sleeved shirts, durable pants (pockets come in handy!), good headwear for sun protection, and sturdy boots, we begin loading up the van for departure to the field. The equipment we bring from our base can include things like Total Stations for topographic mapping and surveying, toolboxes with smaller equipment such as trowels, tape measures, handpicks, and hand pruners, and various bags and baskets to store other tools. Some of the larger equipment, like shovels, pickaxes, and wheelbarrows are stored on-site at the excavation in Teotihuacan. At approximately 7:00 AM, the team sets out from our base in San Juan Teotihuacán to the Teotihuacan archaeological zone.
A bright and early morning in San Juan Teotihuacán brings a nice view of hot air balloons flying over the site.
Once we arrive at the site, work begins right at 7:30 AM. We greet the local fieldworkers working with PPCC, who begin helping us unload equipment from the van and storage. As PPCC works during the summer months in Central Mexico, when it can often rain in the afternoon and throughout the night, at the end of each workday we cover the excavation pits with large tarps to protect them – naturally, in the mornings we remove these large tarps to begin working. Usually, we also prop these tarps up over the excavations to provide shade for work in the warm summer days. Afterwards, we go right back to excavating where we had finished the day before, or we open a new excavation pit entirely.
On a particularly rainy day in Teotihuacan, tarps help cover the excavation and protect the soil and architecture inside from getting wet
Before the Dig
Before going any further, it’s important to describe how we do excavation. Imagine that you have a layer cake with various flavors stacked vertically inside. As you “dig down” through the cake, you may realize that the flavor is vanilla at the top, chocolate in the middle, and then strawberry at the bottom. Eating a layer cake and noticing the changes in flavor is quite like what archaeologists do to systematically excavate a site! We conduct what is known as “stratigraphic excavation”, or a method of digging in which one excavates layer by layer, starting new layers upon noticing changes in soil type, and thus potentially the start of an earlier time period in the site’s history. For example, artifacts found in a layer closer to the surface can be considered to be younger than artifacts found in layers further down, and by taking note of the changes in soil layers (or strata). We can make rough estimations of artifact age and exact locations in the dig by situating them within different strata.
Change in soil along a profile of the excavation in the Plaza of the Columns.
There are a number of things we must measure and do before even putting trowels to turf. Before opening a new pit or starting to dig into a new layer, we take a number of notes on things like the geographic coordinates of the layer or qualitative descriptions of the soil. To discuss this further, it is important to first describe how PPCC actually organizes and plans the excavation. Like many other archaeological digs, PPCC operates on a square grid pattern laid across the excavation site – any new pit opened generally follows the delimitations of the grid, the squares of which measure 3 x 3 meters. Grids are marked by sequential numbers from east to west and sequential letters from south to north. To refer to different parts of the excavation we call them by these names; for example: “Let’s open a new pit in square 18M” or “Let’s expand the pit in square 7K south to square 7J and then west to 8J”. This helps us to spatially situate the dig and make clear, definite explanations of site locations (e.g. “the wall we found extends from 7K to 7J”).
In order to start digging a new layer, first we take survey points using the Total Station. This enables us to have spatial information of the excavation and ensure that we are digging in alignment with the overall grid. This involves setting up the Total Station and a “backsight”, which is another device that the Total Station uses as a point of reference to gauge its own location. The Total Station and backsight are placed at specific locations at the site which have known XYZ coordinates in order to situate the devices in geographical space. All that remains is to point the lens of the Total Station at the surface of the layer we want to excavate, and capture four measurements at the northwest, northeast, southwest, and southeast corners of the square. Together with a telescoping ruler and a “miniature back sight” that the Total Station uses for reference, we get the XY coordinates and elevation in meters above sea level of the four corners of the square.
PPCC Team Working with Total Stations
Let’s assume we are opening a new excavation square. Ensuring that the new square is situated where we want it and that it is in line with the rest of the grid, we place four metal rods into the ground at the corners of the square and tie a string between all four, creating a visible box over the surface of the earth. Next, we write down all the information we measured such as surface elevations and XY coordinates. We also evaluate the soil and take notes on its composition, compaction, texture, and possible intrusions like roots or stones, as well as compare the color of the soil to our Munsell Soil Chart, which is a tool that helps us describe the color of soil in a standardized manner. In general, we take a multitude of notes before digging a new layer such as our general objectives, a paragraph or so describing of the layer and its contents, among other quantitative and qualitative data. These Total Station measurements and written descriptions are not just done for the start of an excavation, but for every single time we change layers due to noticing a change in soil texture, color, or any other sign.
After writing down as much info as possible, we take a photo of the layer before starting to dig so that we have an idea of what it looked like before we literally “dig in”. If we are taking a photo of a layer of soil, we have to clean up the layer before we take a photo so that things are as clear as possible – after doing so with a handful of brushes, brooms, and dustpans, we usually also need to put up a tarp to provide shade, so that shadows cast by the sun do not disturb the image. Often this is already done, as we put the tarps over our heads for shade, but sometimes you need a helping hand or two to provide some additional shadows for a better-quality image. Finally, alongside a scale and north arrow for reference, we place a whiteboard in the pit with information such as the date, name of the structure or the Front in which we are excavating, name of the square, highest elevation of the surface, and other notes that help explain what we are looking at in the photo. After taking the photo with both on-site iPads and digital cameras, we can (finally!) start to dig.
Photo taken before the start of excavation, with whiteboard, scale, north arrow, and box boundaries indicatedCleaning up a layer and preparing a whiteboard prior to taking a photo
Doing the Digging
Fieldworkers put excavated soil into buckets which are then carried over to a nearby mesh screen. The soil is sifted through the screen, as smaller soil particles fall through, and larger objects are caught in the mesh wire. These larger objects can range from simply large natural stones to actual artifacts, such as ceramics and stone tools or organic materials such as charcoal or bones. These materials are placed in plastic bags for safekeeping. Organic materials like charcoal are treated with more care, extracted with sanitized trowels and placed in special Whirl-Pak bags, as charcoal can be used in further analyses like radiocarbon dating. This way of handling helps keep it uncontaminated, as human hands can contain contaminants that will disturb further analysis. All the dirt and rocks we find in the excavation are tossed into piles around the edges of the excavation – when the excavation is all over at the end of the season, we actually throw all the soil and rocks back into the earth in a process called “backfilling”, re-covering the architecture and exposed soil such that it looks like we were never even there.
PPCC fieldworker screens buckets of soil to find materials.PPCC team excavates a pit with trowels, handaxes, pans, buckets, brushes and shovelsRock piles at TeotihuacanBackfilling at the end of the season
We can find things on a much larger scale than just artifacts, and sometimes an excavation can unearth whole features such as walls, plaster floors, and postholes constructed by the ancient inhabitants of Teotihuacan. Obviously, we can’t exactly place these in little plastic bags, so upon encountering something like a wall or floor we do our best to preserve it in its original state and take as many measurements as we can of its location, height, length and width, general form, and relation to other features. We may even take samples of them for further analysis by doing things like drilling into a floor to retrieve a small piece or scraping small parts of walls off. Additionally, we can also take samples of the soil, often that which is above ancient floors or adjacent to material deposits, for analysis – these samples are treated with a similar care to charcoal samples, as we also try to avoid contaminating these as well.
Once it is time to change layers, we take all the bags of materials found in that layer, seal them, and attach a tag with information such as a bag number, the type of material, the name of the Front, structure, and layer in which the materials were found, and the elevations of the layer derived from our Total Station measurements. All of this information is also entered into a material database through our on-site iPads. The materials are then placed in baskets and loaded into the van, where they will be taken to an on-site facility for analysis and storage at the end of the day.
Writing tags for soil samples under the “casita”.
Throughout the process of digging layers and finding materials, we continue to do things like taking photos and Total Station measurements. Once we feel we have excavated down to an appropriate endpoint, we take aerial photos of the square with a drone and take multiple photos of the excavation for a process known as photogrammetry, which can produce digital 3D models of the excavation by stitching together photographs taken from different angles. One important process of archaeological documentation is profile drawing, which involves hand-drawing a sketch of the stratigraphic layers visible on the sides of the excavation. This involves laying a string horizontally across the side of the excavation at a certain height above the surface. Next, we measure how far down from the string different objects are, along this horizontal axis. These objects include the various layers like the earth’s surface or construction fill, intrusive rocks, or even architectural features such as floors. It is also possible to draw profiles using the total station, to measure exact distances, this is useful when drawing profiles that are especially large or deep. A fully drawn profile gives you detailed stratigraphic information as well as approximate architectural dimensions, which prove invaluable for further analysis.
Profile drawing in the Plaza of the Columns.
All Work and No Play?
Excavation is a hard and arduous work – but we’re not constantly in the pits, digging, drawing, or writing from morning to evening. From about 12:00 to 1:00 PM, after a good 5 hours or so of work, we take a break to eat and relax, and some members of our team find it a good time to take a nap.
Naptime at Teotihuacan
Far from boring, the PPCC pit is a lively setting. Throughout the excavation we chat, visit and check out each other’s excavations and other Fronts, have small snacks and drinks in our little “casita” shack, and listen to music, amplified to the whole excavation through the ingenious process of placing a Bluetooth speaker in a bucket. At times we have visitors who come to take a look at the excavation, and PPCC team members help to show them around and explain a little bit about what we are doing and the amazing things we are finding every day on the dig. The visitors aren’t always human, either!
Animal friends visiting the excavation
At around 4:00 PM, at the end of a long day of work, it is time to pack up for the day. We place the large tarps back over the excavation and secure them down with large stones, and load the tools like trowels, brushes, and Total Stations back into their toolboxes and storage cases. Wheelbarrows filled with shovels, pickaxes, and plastic stools get wheeled back to the storage shed. The PPCC team, archaeologists and fieldworkers alike, say their goodbyes and start going home, and the van loaded with all the materials collected that day goes to drop them off. After all is said and done, the team returns home for dinner, rest, and – hopefully – a nice shower.
Work on the project isn’t always being done on-site, however. On days when we are not in the field, often at the end of the work week, we spend time back at the base processing everything we have collected that week. Photos are described and registered in a database, all the notes and descriptions made of soil layers and findings are consolidated into a project digital notebook, profile and plan drawings are digitized in Adobe Illustrator, and Total Station points are saved and stored on project computers. All of this is done to help with writing the end-of-season report, to ensure that our findings are properly documented and the information we uncover is saved for future research and further excavations.
Life at the dig in Teotihuacan is anything but dull and is certainly far more complex than just picking a site and digging straight down. From artifact tagging and bagging, to profile drawing, to Total Station survey, and more, our team thoroughly plans and carries out the excavation of the site such that we can obtain as much information as possible in a relatively small amount of time about the activities, architecture, materials, and culture of ancient Teotihuacan. Now, the next time you read an article detailing a new archaeological find or take a look at an ancient artifact in a museum, you can imagine all the hard work and careful effort going on behind the scenes so that ancient history and culture is preserved for us to learn more about our past.
