The great basalt disc most people associate with Tonatiuh, the so-called Aztec Calendar Stone or Piedra del Sol, was rediscovered by chance in December 1790, when workers repaving the main square of Mexico City, on the site of the old Aztec capital, unearthed the massive multi-ton monolith along with the equally famous Coatlicue statue nearby, both buried since the Spanish destruction of Tenochtitlan's temples over two and a half centuries earlier. The stone was set up for public display, eventually finding a permanent home in the National Museum of Anthropology, and its central image, a face with tongue protruding between flint knives, surrounded by the day-signs and cosmological bands, was long assumed straightforwardly to depict Tonatiuh, the daytime sun of the Fifth Age. That identification, however, is not universally accepted among specialists.
Some scholars have argued the central face more likely represents Tlaltecuhtli, the earth deity associated with sacrifice and the devouring underworld, or a version of the night sun, Yohualtecuhtli, rather than Tonatiuh in his usual daytime guise, pointing to iconographic details that recur elsewhere in association with those other deities more than with clearly labeled images of Tonatiuh. The debate has not been resolved, and modern museum labeling and popular explanation still generally default to Tonatiuh, both because of long tradition and because the monument's function as a solar and calendrical record makes a sun-god reading intuitive, even though the stone's own carved face may, in the judgment of a meaningful number of specialists, actually belong to one of his underworld or earth-bound relatives.