During the last construction stage of the Great Temple, the north, south and east sides were enriched with the platform of the Coatepantli (serpent wall). The bodies of the reptiles, formed with stones and a mortar of lime and mud, were designed with curvatures to appear to be in movement. In the heads, carved in stone, the fangs, the slit eyes and the forked tongue of the reptiles can be appreciated. Another realistic feature is observed in three small steps that top the body simulating the ring or rattle characteristic of the Crotalus triseriatus (rattlesnake). If you look closely, in some specimens there are still traces of the colors (red, blue, black and green) that covered the bodies.