Excerpts from “Fingerprints of the Gods” by Graham Hancock (Chapter 22) that I found fascinating:

“What Harleston’s investigations had shown was that a complex mathematical relationship appeared to exist among the principal structures lined up along the Street of the Dead (and indeed beyond it). This relationship suggested something extraordinary, namely that Teotihuacan might originally have been designed as a precise scale-model of the solar system. At any rate, if the centre line of the Temple of Quetzalcoatl were taken as denoting the position of the sun, markers laid out northwards from it along the axis of the Street of the Dead seemed to indicate the correct orbital distances of the inner planets, the asteroid belt, Jupiter, Saturn (represented by the so-called ‘Sun’ Pyramid), Uranus (by the ‘Moon’ Pyramid), and Neptune and Pluto by as yet unexcavated mounds some kilometres farther north.

If these correlations were more than coincidental, then, at the very least, they indicated the presence at Teotihuacan of an advanced observational astronomy, one not surpassed by modern science until a relatively late date. Uranus remained unknown to our own astronomers until 1787, Neptune until 1846 and Pluto until 1930. Even the most conservative estimate of Teotihuacan’s antiquity, by contrast, suggested that the principal ingredients of the site-plan (including the Citadel, the Street of the Dead and the Pyramids of the Sun and the Moon) must date back at least to the time of Christ. No known civilization of that epoch, either in the Old World or in the New, is supposed to have had any knowledge at all of the outer planets – let alone to have possessed accurate information concerning their orbital distances from each other and from the sun.”

“There was no archaeological evidence that this enormous enclosure had ever served as a citadel – or, for that matter, that it had any kind of military or defensive function at all. Like so much else about Teotihuacan it had clearly been planned with painstaking care, and executed with enormous effort, but its true purpose remained unidentified by modern scholarship.28 Even the Aztecs, who had been responsible for naming the Pyramids of the Sun and the Moon (an attribution which had stuck though no one had any idea what the original builders had called them) had failed to invent a name for the Citadel. It had been left to the Spaniards to label it as they did – an understandable conceit since the 36-acre central patio of La Ciudadela was surrounded by massively thick embankments more than 23 feet high and some 1500 feet long on each side.”

“My walk had now brought me to the western extreme of the patio. I climbed a steep set of stairs that led to the top of the embankment and turned north on to the Street of the Dead. Once again I had to remind myself that this was almost certainly not what the Teotihuacanos (whoever they were) had called the immense and impressive avenue. The Spanish name Calle de los Muertos was of Aztec origin, apparently based on speculation that the numerous mounds on either side of the Street were graves (which, as it happened, they were not).

As I walked steadily northward towards the still-distant Moon Pyramid, it seemed to me that this theory had several points in its favour. For a start the ‘Street’ was blocked at regular intervals by high partition walls, at the foot of which the remains of well-made sluices could clearly be seen. Moreover, the lie of the land would have facilitated a north-south hydraulic flow since the base of the Moon Pyramid stood on ground that was approximately 100 feet higher than the area in front of the Citadel. The partitioned sections could easily have been filled with water and might indeed have served as reflecting pools, creating a spectacle far more dramatic than those offered by the Taj Mahal or the fabled Shalimar Gardens. Finally, the Teotihuacan Mapping Project (financed by the National Science Foundation in Washington DC and led by Professor Rene Millon of the University of Rochester) had demonstrated conclusively that the ancient city had possessed ‘many carefully laid-out canals and systems of branching waterways, artificially dredged into straightened portions of a river, which formed a network within Teotihuacan and ran all the way to [Lake Texcoco], now ten miles distant but perhaps closer in antiquity’.”