A model of the pyramid
The orientation of the structure may hold some anthropological significance. The pyramid is oriented slightly northwest of the horizon point of the setting sun on two days a year, August 12 and April 29, which are about one divinatory calendar year apart for the Teotihuacanos. The day of August 12 is significant because it would have marked the date of the beginning of the present era and the initial day of the Maya long-count calendar. In addition, many important astrological events can be viewed from the location of the pyramid that are important in terms of both agriculture and belief systems of the ancient society.
The pyramid was built over a man-made tunnel leading to a "cave" located six metres down beneath the centre of the structure. Originally this was believed to be a naturally formed lava tube cave and interpreted as possibly the place of Chicomoztoc, the place of human origin according to Nahua legends. More recent excavations have suggested that the space is man-made and could have served as a royal tomb.Šprajc, Ivan (2000). "Astronomical Alignments at Teotihuacan, Mexico". Latin American Antiquity 11 (4). p. 410. Recently scientists have used muon detectors to try to find other chambers within the interior of the pyramid, but substantial looting has prevented the discovery of a function for the chambers in Teotihuacan society.
Recovered artifacts
Comparison of approximate profiles of Pyramid of the Sun with some notable pyramidal or near-pyramidal buildings. Dotted lines indicate original heights, where data is available.
Only a few caches of artifacts have been found in and around the pyramid. Obsidian arrowheads and human figurines have been discovered inside the pyramid and similar objects have been found at the nearby Pyramid of the Moon and Pyramid of the Feathered Serpent in the Ciudadela. These objects may have represented sacrificial victims. In addition, burial sites of children have been found in excavations at the corners of the pyramid. It is believed that these burials were part of a sacrificial ritual dedicating the building of the pyramid. Just recently[when?] a man's body was found buried in the Moon Pyramid. The man was apparently buried alive with art, gold and sacrifices for the gods.