A five-year dig under old buildings near Mexico City’s Templo Mayor Aztec ruins has so far found a total of 603 skulls that they are believed to date to between 1486 and 1502.
The sacrificed skulls, found about 3.5 yards (3.2 meters) below street level, included some from women and children and officials saw the huge pile of skulls as a sign of the power and prestige of the pre-Hispanic city.
“It is an important testament to the power and greatness achieved by Mexico-Tenochtitlan,” said Alejandra Frausto, Mexico City’s culture secretary.
Such racks, known as Tzompantli, were where the Aztecs displayed the severed heads of sacrificed victims on wooden poles pushed through the sides of the skull.
Paintings and written descriptions from the early colonial period showed descriptions of such racks, but institute archaeologists said the Mexico City discovery was different.
Part of the platform where the heads were displayed was made of rows of skulls mortared together roughly in a circle, around a seemingly empty space in the middle.
All the skulls were arranged to look inward toward the center of the circle, but experts don’t know what was at the center.
Skulls may have displayed on racks while fresh, and once the flesh had rotted off, they may have been mortared together.
The dig has been carried out underneath a series of buildings, some of which are considered historically valuable.
Periodic excavations carried out since 1914 suggested a ceremonial site was located near the site.