(Getty Images)| In Mexico's ancient city of Teotihuacán – a UNESCO World Heritage Site that once boasted a population of more than 125,000 people – visitors will find the Pyramid of the Sun.

The green mask was found at the The Pyramid of the Sun, in southern Mexico, is part of a famous ... "What can be found inside them will help unravel the relationship this ancient metropolis ...

Pyramid of the Sun and Pyramid of the Moon, Teotihuacán, State of Mexico Taking a quick trip away from the Maya world and up to the Valley of Mexico puts us in the heart of Teotihuacán.