Disk of Coyolxauhqui which was found during construction in Mexico City in 1978.  Its discovery lead to the excavation of the Templo Mayor
<a href="//commons.wikimedia.org/wiki/User:Thelmadatter" title="User:Thelmadatter">Thelmadatter</a>
2008-03-22
<span class="int-own-work" lang="en">Own work</span>