The 20-centimeter (7.8 inch) stucco mask was found by a team with the National Institute of Anthropology and History (INAH) during an investigation of the temple’s ancient drainage system. Palenque sits in the southern state of Chiapas, on the border of Guatemala. According to Institute Director Diego Prieto, the mask appears to show the face of K'inich Janaab' Pakal – also known as Pacal the Great. If it is, in fact, Pacal, the experts say it would be the first of its kind. The mask includes wrinkle lines around the mouth and cheeks, which would make it ‘the first representation...