Archeologists have discovered the ruins of an 800-year-old Aztec pyramid in the heart of the Mexican capital that could show the ancient city is at least a century older than previously thought.
In this July 27, 2016 photo,tourists sit at the midway point of the Pyramid of The Moon viewing the ancient Pyramid of the Sun, back right, at the ruins of Teotihuacan in Teotihuacan, Mexico. Ross D.