Work heated up again and two weeks passed before I realized that I didn't post the answer to the last mystery archaeology picture. To recap, here is the picture.
It's a carved panel in the doorway of the temple at the top of the Pyramid of Kukulcan, aka El Castillo, in Chichen Itza. Note the paint is still visible after a thousand years due to the arid conditions of the Yucatan peninsula.
Many of you were confused as to whether it's Maya or Aztec. That's because I threw a tricky curve ball at you. Many of the works of art in Chichen Itza display a highly cosmopolitan flavor, often with Central Mexican styles thrown in. To explain this similarity, archaeologists and historians proposed that the semi-historical Toltec king Topiltzin Ce Acatl Quetzalcoatl was exiled from Tula, the capital of the Toltec state in Central Mexico, traveled across the Gulf of Mexico to the Yucatan Peninsula, and took over Chichen Itza. However, recent research into Chichen Itza proved that it thrived during the Late and Terminal Classic (600-1000 CE) whereas Tula was a Post-Classic city (1000-1200 CE). It is more likely that both cities adopted an inter-regional artistic style that was prevalent throughout Mesoamerica and even to a small extent the American Southwest.