Crossing the outskirts of Mexico City by car on the way to Teotihuacan, the outlines of the mountains can soon be made out on the horizon, especially that of Cerro Gordo. Looking at the pyramids, it is as though some giant had wished to make a faithful copy of those rounded silhouettes, one thinks, and built what for him would be mere mounds of earth. For the Aztecs, Teotihuacan was the place where time had its birth, where the gods decided on the contents and the order of the world. Indeed during the Aztec era, around the 14th century AD, the city had already lain abandoned for many centuries, its past splendor lost in the mists of mythology. It strikes us how difficult it is today to understand the mentality of men who wished to replicate the mountains.
The earliest archaeological evidence from Teotihuacan dates from the first century BC. Immediately after this the city grew enormously, and rapidly became one of the largest cities on the planet at that time, with a population of some 125,000 (Millon 1973,1992). The splendor of Teotihuacan was to last for a few centuries—traces of Teotihuacan art and customs are to be found all over Mesoamerica—until the city vanished from history along with its inhabitants in the 6th century AD. We know very little about them, and nothing about their language, provenance, or end; we have no written remains.
Only the splendid objects they made, which have been found in numerous burial grounds, speak to us, as well as their wonderful architectural achievements, if we are prepared to listen to them.
We know for certain that the two main divinities that existed in Teotihuacan—in fact, we encounter them to some extent in all Mesoamer-ica—were the Rain God and a creator-divinity portrayed as a plumed serpent. We use the Aztec names Tlaloc and Quetzalcoatl for these divinities, since we do not know their original names. The name that we use for the city is also the one given by the Aztecs: Teotihuacan, the City of the Gods.
It is no coincidence that it was given this name. You get a strange feeling, one of unease, especially in the early hours of the morning, before the assault of frenetic tourists, when the city is seen gradually emerging from the mist. You feel the weight, the almost tangible presence of a remote, far-off sense of antiquity—silent and hard to fathom. In the first place, the sheer scale on which the city was conceived is staggering. In fact it was designed meticulously on the base of a main axis 2.5 kilometers long and 40 to 95 meters wide, designated (with a rather inadequate name that some attribute to the Aztecs but that I think more likely to be a Spanish invention) the Avenue of the Dead. Before tracing out the avenue, for reasons that are difficult to hazard and that we shall return to, the nearby San Juan River was canalized so that it intersected with the avenue itself at an angle of 91 degrees, and extensive underground hydraulic works were implemented to drain off rainwater, which was then channeled off into the river. At the far north of the avenue, and on the east side, two large and nowadays anonymous pyramids were erected, traditionally called, without any historical justification whatsoever, Pyramid of the Sun and Pyramid of the Moon (Plates 15, 16). To the southwest, we find another monumental complex, known as the Citadel, which includes a further pyramid, clearly dedicated to the Plumed Serpent, stone heads of which emerge from the terraces at regular intervals. The southern end of the avenue does not appear to have featured any particular structure on it, but this is in itself curious, and new excavations may yet come up with something interesting. What is certain, however, is that the city had no walls or defensive structures of any kind.
Situated in the ideal center of the city, but located laterally in relation to the Avenue of the Dead, the Pyramid of the Sun is one of the largest artifacts in the world. Its base originally had a 215-meter-long side, which then was extended to 225 meters, and it was 63 meters high. Today it is made up of five platforms, but one of these is the result of a disastrous 19th century restoration. There was probably a temple on the top, but we know nothing about its form. Beneath the pyramid there is an extensive artificial grotto, which was used for burials.
The Pyramid of the Moon, smaller but equally elegant, faces on to a large square at the north end of the Avenue of the Dead. Going along the avenue, the silhouette of the pyramid in the distance seems to blend with the profile of the Cerro Gordo; it is as though someone had made a scale copy of the mountain. The same impression is gained when the Pyramid of the Sun is glimpsed from the north, with the profile of the Cerro Patlachique in the background (Broda 1993, 2000).
It was customary in Mesoamerica to remodel pyramids cyclically, that is, incorporating an existing structure into a larger one, with the outer one acting as a kind of wrapping or casing. It had been known for considerable time that the Pyramid of the Moon must have contained previous structures, but only in 1998 were systematic excavations begun. Today we know that the structure was rebuilt (or "accreted") seven times, and that ritual offerings, consisting of objects and animal and human sacrifices, were laid on each of these layers.
We know only a little about how the city was planned. Imagine being a town planner who is told to design the plan of a city that is to be built. Certainly, today this is unimaginable, but we could perhaps think in terms of, say, a housing project. The planner would adopt the most anthropo-centric criteria possible (taking account of the needs of the future inhabitants), adapting them when faced with external problems relating to the geology or morphology of the terrain in question (such as a river flowing through the area, which would entail a modification). Where possible the planner would follow criteria of simplicity, preferring right angles and choosing the main directions according to the best possible ventilation or sun warming. Alternatively, if we are talking about a more inventive architect, he would try perhaps to break the mold, with fanciful constructions, bold angles, and unexpected shapes.
In Teotihuacan, neither method was adopted. But the planning was by no means a random hit-or-miss affair. The planners decided that the city should be built on the basis of a grid directed toward the cardinal points, but the cardinal points were to be decided by the planners; instead of the north they used the direction of azimuth 15.5 degrees east of north and instead of east they used the direction of azimuth 16.5 degrees south of east. To survey their chosen directions the builders used pecked crosses, concentric circles carved on the rocky terrain, at the center of which a pole was placed to act as a reference for surveying. It is as though for some reason there existed a Teotihuacan north-south axis displaced 15.5 degrees to the east of ours, on which the Avenue of the Dead was oriented, and a Teotihuacan east-west axis, offset 16.5 degrees to the south of ours (I shall refer to these Teotihuacan cardinal directions with a "T-" prefix).
Our cardinal axes, inherited from Greek and Roman city planning, form an angle of 90 degrees, that is, they are perpendicular to each other; the two Teotihuacan axes, however, do not form a right angle, but an angle of 91 degrees. Yet considering the accuracy of the Teotihuacan architects, we have to deduce that this choice was deliberate. So if we want to visualize how the city was designed, we cannot just think about our cardinal directions arranged in a cross and rotate them with an a rigid movement because we also have to rotate the east-west axis one degree further towards the south. Why? We merely have to note that the planners were forced to build an artificial canal to divert the river in order to fit the direction in with their overall plan, to conclude that the cardinal T-axes do not conform at all with the features of the ground. To try to understand the reasons behind such a complex urban system, we must realize that Teotihuacan is one of the most extraordinary examples of sacred landscape, a place where a monumental replica of the natural landscape bestowed power and prestige. The mountains were indeed undoubtedly sacred and this would explain the orientation of the Avenue of the Dead toward the Cerro Gordo, the fact that the Pyramid of the Moon is placed on the line of sight of its counterpart (the Cerro Gordo), and the fact that the Pyramid of the Sun faces its counterpart Cerro Patalachique (which explains why it was located on the east side of the avenue).
All this was surely the driving force behind the choice of the place and the structure of the city. As I have said, at Teotihuacan the idea was to replicate the mountains. Nevertheless, the extension of the Avenue of the Dead does not pass over the summit of Cerro Gordo (it is off by a couple of degrees), and since Teotihuacan designers had no problems in determining directions with errors well below half a degree, it follows that the precise direction of T-north must have a further significance.
One sensible suggestion that might explain the T-north orientation hinges on the fact that the direction orthogonal to it points to the setting of the Pleiades (Dow 1967). In Teotihuacan in the first centuries AD, the Pleiades underwent heliacal rising on approximately the same day as the first zenith passage of the sun (the zenith passage occurs when the sun passes vertically above the observer's head at noon; see Appendix 1), and thus their first appearance may have served as a signal for this important phenomenon. Further, the Pleiades culminated near the zenith at Teotihuacan, and it may be that this coincidence strengthened the link between these celestial bodies and the sun. According to many scholars (Aveni 2003, Drucker 1977, Sprajc 2000a,b), the passage of the sun to its zenith should also be at the origin of the orientation of the other axis, due to a rather complicated mechanism, which I now shall try to explain.
The T-east axis does not indicate the setting of the sun on the dates it reaches the zenith at the latitude of the city; these dates are May 18 and July 24, whereas the sun sets in alignment with T-east on April 29 and August 13. It should be noted, however, that the latter two dates are more distant from the summer solstice than the former two; hence, there undoubtedly exists a latitude that is lower than that of Teotihuacan, at which the sun passes to the zenith on those dates. We should also note that these dates are separated by 260 days. In the whole of Mesoamerica (especially among the Mayas, as we shall see in more detail in Chapter 9), the calendar included two distinct cycles, one of which was 260 days. It is likely that this is the number of days that separates the two zenith passages of the sun in the place where the calendar was originally calculated, which should correspond to the parallel at 15 degrees north latitude. The great classical Mayan city of Copan, in modern Honduras, is located on it (Malmstrom 1978,1997), but the calendar had already been documented in earlier times (in the final Olmec period, around the 4th century BC), and thus it is more likely that it was codified at a preclassical site, possibly Izapa, in Mexico, which is situated on the same parallel as Copan.
Thus, the T-east orientation seems to have the aim of indicating the number of days of the 260-day calendar. Since, as has been said, Teotihuacan is much further north than the places where the calendar was codified, such an orientation did not correspond to any special astronomical phenomenon, such as solstice or zenith passages. It thus represents an example of codification of astronomical information in an urban context.
Some scholars have rejected this explanation and more generally the interpretation of the cycle of 260 days based on the zenith passages, putting forward other explanations (such as the average human gestation period) or attributing it to chance. It is difficult to gain definitive proof that the astronomical-symbolic interpretation is the correct one. But one fact is certain: the Teotihuacan people's interest in the zenith passages of the sun was enormous. So interested were they in this phenomenon that they endeavored to find the place where the Sun "turns back.''
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