Coatepantli

Many researchers have suggested that the coatepantli were used to mark the boundary between ceremonial and non-ceremonial land,[4][5] and at times the word has been used to signify any wall which encloses a sacred space, notably in Tlatelolco.

[4][8] One interpretation of these carvings is that the snakes represent the earth consuming the dead or the need for human sacrifice to appease the gods.

[5] Another theory asserts that the skeletons are representations of past kings or warriors and that the serpents, rather than being symbols of the earth, are rather markers of royalty.

[7]The wall at Tenayuca is 170 meters long and features 138 sculpted rattle snakes on three sides of the base of the temple pyramid.

[9] Based on second-hand accounts, the wall at Tenochtitlán was thought for many years to have enclosed the entirety of the sacred precinct of Tenochtitlán and consist of numerous snakes,[4] but archaeological work in 1981 revealed that the sacred precinct of the city extended beyond the coatepantli and that the coatepantli consisted of two walls in the form of large snakes with painted heads, surrounding the Templo Mayor.