Piramide Del Sol - world's 3rd largest pyramid - Base 222m x 4; height 70m - built @ 100AD
Teotihuacan - Mexico's largest ancient city. (50 km northeast of Mexico City). Built between 100 AD to 800 AD when a variety of factors led to its decline and abandonment. Covered more than 20 sq km and is said to have contained 125,000 people.