Pyramid of Tenayuca
State of Mexico, Mexico
Double pyramid with a serpent wall. Date: First phase around 1250, last between 1450 and 1500 according to INAH; Wikipedia gives 1299 and 1507.
Double temple dedicated to Tlaloc and Huitzilopochtli. The last phase measures 62 by 50 m, and the base is surrounded by a platform with about 140 serpent sculptures; sources count six or seven building phases.